CA2000858A1 - Carbon fibers having high strength and high modulus of elasticity and polymer composition for their production - Google Patents

Abstract

ABSTRACT
Silicon-containing carbide fibers having high strength and modulus of elasticity, and polymer com-positions for production thereof. These fibrers are inexpensive and very useful as reinforcing fibers for composite materials comprising plastics, carbons, metals, etc. as a matrix. These polymer compositions are also useful as a matrix of the above composite materials.

Description

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SPECIFICAIION
CARB~N FIBERS ~VING ~IGB S~ENGT~ AND
~IIG~ MODUL~S O~ ~L~Sl'ICITY ~ND POLY~R
CO~PnSITIO~ FOR T~EIR PROD~C~ION

T~CE~OLOGIC~L FIELD
This invention relates to carbon fibers having h gh strength and high modulus of elasticity, and polymer compositions for their production. More specifically, it relates ~o carbon fibers csntaining silicon, or both silicon and a specific transition metal atom, and polymer composi~ions for their production.
BAC~GRO~ND TEC~OLOGY
Carbon fibers have light weight, high strength and high modulus of elasticity, and thereore, their utility is not only in sporting and leasure qoods, but has been expanded to a wide range of fields including aircraft, automobiles and building materials.
PAN-type carbon fibers derived from poly-acrylonitrile as a raw material and pitch-type carbon fibers obtained from petroleum and coal pitches as raw materials are known as the carbon fibers.
Japanese Laid-Open Patent Publication No.
223316/1984 discloses a process for producing fibers having high strength and high modulus of elasticity, which comprises ; ta) hydrogenating a pitchr separating the solid from the hydrogenation product, and removing low-bsiling components by distillation to obtain a hydrogenated pitch, (b) heat-treating the hydrogenated pitch under reduced pressure to give a mesophase pitch (containing not more than 90 ~ by weight of mesophase carbon and at least 30 % of optically anisotropic fibers), and there-after ~c) melt-spinning the mesophase pitch, and rendering the f.ibers infusible and carbonize them.
International Patent Laid Open W087/G5612 and Japanese Laid Open Patent Publication No~ 209139/1987, the corresponding Japanese priority application, dis-closes an organopolyarylsilane being soluble in organ~csolv2nts and comprising organosilane segments in which the skeletal portion is composed mainly of carbosilane and polysilane, said segments being connected at random via silicon-carbon linking groups.
Laid-Open International Patent ~0 87/05612 and Japanese Laid-Open Patent Publication No. 21501S/1987, the corresponding Japanese priority application, disclose continuous SiC-C type inorganic fibers composed of mol-ecules having carbcn and SiC as main constituents and 15 containing 5 to 55 ~ by weight of Si, 40 to 95 % by weight of C and 0.01 to 15 % by weight of 0, said in-organic 1bers showing excellent thermally resistant strength and oxidation resi~tance with a volume re-sistivity of 10 to 10 3 ohms~cm.
The above laid-open specifications describe a process for producing inorganic fibers having properties intermediate between the silicon carbide fibers and carbon fibers, which comprise mixing an organic solvent-soluble component of a coal or petroleum pitch with a polysilane, and reacting the mixture under heat to syn-thesize an organopolyarylsilane, and spinning it and rendering the fibers infusible and curing the fibers.
However, in the above process, a pitch quite free from an organic solvent-insoluble portion is selected as one of the starting materials, and in the production of the organopolyarylsilane, the reaction is carried out under such conditions that no organic solvent-insoluble portion is formed.
Accordingly, the resulting product as a spin-ning material does not at all contain the above insolubleportion in the mesophase, which is said to be the most important component for development of stEength by carbon fibers~
Inorganic fibers obtained by spinning~ render-ing the fibers infusible and curing them gives a dif-fraction line ~002) corresponding to the graphite cry-stals of caxbon under certain condit:ions~ but no orien-tation inherellt to pitch fibers i5 noted~ Furthermoret in the process described in the above patent documents, the heat resistance o the fibers in an inert gas is enhanced as the proportion of the pitch content in-creases~ But~ on the contrary, the oxidation resistance of the fibers is decreased, and moreover~ their mecha-nical characteristics tend to be reduced markedly.
3apanese Laid-Open ~aten~ Publication No.
7737/1987 discloses a composite material comprising a matrix of a plastic and as a reinforcing material hybrid fibers consisting of inorganic fibers containing silicon, titanium (or zirconium), carbon and oxygen and at least one kind of fibers selected from the group consisting of carbon fibers, glass fibers, boron fibers, aramid fibers and silicon carbide Eibers having carbon as a core.
Japanese Laid-Open Patent Publication No.
266666~1986 discloses a coontinuous fiber bundle for use in a composite material, said fiber bundle comprising continuous fibers of ceramics (silicon carbide, silicon nitride, aluminas etc.) or a heat-resistant material (carbon~ metals, etc.) and short fibers, whiskers or powders of the same material as above adhering to the surface of the continuous fibers.
Japanese Laid-Open Patent Publication No.
195076/1985 discloses a method of improving the surface hardness and oxidation resistance of carbon fibers, which comprises adhering or contacting a silicon-containing material to or with the surface of a caLbonaceous material, melting the silicon-containing material to form a modified layer composed of silicon carbide and carbon on the surface.

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3apanese Laid-Open Patent Publlc~tion No.
2S1175/1985 discloses a process for producing a molded article composed of silicon carbide and carbon, which comprises slowly o~idi~ing a molded carbon article at 400 to 600 C to render it light in weight and porous, and then allowing a silicon-containing material ~o penetrate into the pores and react at a t:emperature above the meling point of the silicon-containing materialr It is an object of this invention to provide novel fibers having high strength and high modulus of elastici~y.
Another object of this invention is to provide fibers having high strength and high modulus of elas-ticity containing crystalline carbon oriented in the 1~ direction of the fiber axis and consisting essentially of silicon, carbon and oxygenO
Still another object of this invention is to prov~de fibers having high strength and high modulus of elasticity which when used as a reinforcing material for a composite material, shows excellent we~tability with a matrix material.
Yet another object of this invention is to produce high strength and high modulus fibers which has much higher modulus of elasticity than silicon carbide 2S fibers and excellent oxidation resistance with their oxidation resistant temperature being higher by about 200 to 300 C than conventional pitch-type carbon fibers or the PAN-type carbon fibers.
A further object of this invention is to pro-vide a polymer composition suitable for production of the fibers of this invention.
Other objects of this invention along with its advantages will become apparent from the following de-scription.
35According to this invention, the above objects and advantages of this invention are firstly achieved by ~t ~9 l~a~

fibers having high strength and high modulus of elasti-city comprising ~i~ crystalline carbon oriented suhstantially in the direction of the fiber axis, (ii) amorphous carbon and/or crystalline carbon oriented in a direction different from the fiber axis direction, and (iii) a silicon-conta.ining component consisting essentially of 30 to 70 % by weight of Si, 20 to 60 % by weight of C and OOS to 10 % by weight of O, the propor-tions being based on the total weight of silicon, carbon and oxygenO
The above fibers of the inYention Sto be some-times referred to as the first fibers of the invention) can be produced by a process which comprises preparing a spinning dope of a polymer composition comprising (A) an organic silicon polymer resulting from random bonding of a plurality of at least one type of bond selected from the group consisting of units re-presented by the following formula (a) Rl -Si- ~ a) wherein Rl and R2, independently from each other, represent a hydrogen atom, a lower alkyl group, a phenyl group or a silyl group ~-SiH3), either via methylene groups (-CH2-) or both via methylene groups and directly, (B) a polycyclic aromatic compound in the s~ate of a mesophase, a premesophase or a latently anisotropic phase, and (C) a polycyclic aromatic compound which is optically isotropic but is not in the state of a premeso-phase or a latently anisotropic phase, at least a part of componen~ (A) being chemically bound to component (B) and/or component (C~; spinning the spinniny dope; rendering the sp~un fibQrs infusible under tension or no tension, and pyrolyæing the infusible fibers at a temperature of 800 to 3,~Q0 C in vacuum or in an inert gaseous atmosphereO
The polymer composition used in the spinning step has been provided for the first time by the present inventors, and constitutes part of the invention~
The novel polymer composition can be produced by heating the organic silicon polymer (A) and a pitch which has no excessive heat history in an iner~ gas, preferably at a temperature of 250 to 500 C, and melting the resulting reaction product at 200 to 500 C together with a pitch mainly having a mesophase, a premesophase or a latently anisotropic phase.
The novel polymer composition and a process for its production will first described~ and then, the above fibers of the invention and a process for production thereof.
The organic silicon polymer (A) is ob~ained by the random bonding of the plurality of the bond units of formula (a) via methylene groups (-CH2~) or via methylene groups and directly.
In formula ~a), Rl and R , independently from each other, represent a hydrogen atom~ a lower alkyl group, a phenyl group or a silyl group (-SiH3). Examples of the lower alkyl group are linear or branched alkyl groups having 1 to 4 carbon atoms such as methyl, ethyl, propyl and butyl groups.
The organic silicon polymer ~A) can be pro-duced, for example, by rea~ting dimethyldichlorosilane and metallic sodium to produce polymethylsilane, and heating the polymethylsilane at a temperature of at least 400 C in an inert gas. In this example, an organic silicon polymer in which a plurality of units of formula (a~ wherein Rl and R2, independently from each other, are hydrogen and methyl are bonded randomly via methylene groups, or both via methylene groups and directly It will be understood that when part of dimethyldichloro-silane is replaced by diphenyldichlorosilane, an organicsilicon polymer is obtained which has units of formula ~a) wherein Rl and R2 in formula ~a), lndependently from each other, represent hydrogen, methyl and phenyl.
The organic silicon polymer (A) has a weight average molecular weight (Mw) of preferably 300 to l~OOOt especially preferably 400 to 800.
The pitch which has no excessive heat history may be originated from petroleum or coal. In particular distilled oils or residual oils obtained by distilling heavy oils produced by fluidized catalytic cracking of petroleums, or heat-treated products of the distilled oils or the residual oils are preferably used. These pitches are usually optically isotropic ~these pitches will be called optically isotropic pitches hereaEter).
Preferably, the optically isotropic pitches contain 5 to g8 % by weight of components insoluble in organic solvents such as benzene, toluene, xylene and tetrahydrofuran~
These pitches are polycyclic aromatic compounds if their chemical structure is considered, and are pre ferably relatively high-molecular-weight compounds having a weight average molecular weight of about 100 to 3,000.
The weight average molecular weight may be measured directly by gel permeation chromatography ~GPC~ if the pitch does not contain components insoluble in organic solvents. On the other hand, when the pitch has com-ponents insoluble inorganic solvents, the pitch is hydrogenated under mild conditions to change the organic solvent-insoluble components into organic solvent-soluble components, and the molecular weight of the treated pitch is then measured by GPC.

The organic silicon polymer ~A) and the optically iso~ropic pitches are hea~ed and reacted in an inert gas such as nitrogen gas or argon gas, preferably at a temperature of 250 to 500 CO If the reaction temperature is e~cessively low, the reaction tfor ex-ample/ the bonding o~ the aromatic carbons of the pitch to the organic silicon polymer) is difficult. If, on the other hand, the reaction temperature is excessively high, the decomposition of ~he reac~ion product and its con-version to a higher-molecular-weight product occur vigorouslyO
The proportion of the pitch used in this re-action is preferably 83 to 47900 parts by weight per 100 parts by weight of the organic silicon compound~ If the proportion of the pitch used is too small, the amount of silicon carbide component in the finally obtained fibers is large~ and fibers having a high modulus of elasticity are difficult to obtain. If this proportion is exces-sively large, the amount of the silicon carbide component formed becomes small, and fibers having excellent wetting property with respect to the matrix and excellent oxida-tion resistance are difficult to obtain.
The reaction product obtained by the above reaction is then heat-melted with a pitch in the meso-phase, the premesophase or in a latently anisotropicstate.
The mesophase pitch can be prepared by heating a petroleum or coal pitch at 300 to 500 C in an inert gas, and polycondensed while the resulting light frac-tions are removed.
A suitable petroleum or coal pitch contains 5to 98 ~ by weight of components insoluble in an organic solvent such as benzene, toluene, xylene or tetrahydro-furan like the pitch used to react with the organic silicon polymer.
By heat-treating the above starting pitch ~g ~ ?,?

either directly or af~er as required~ csmponents soluble i.n organi~ sGlvent are remo~ed, the mesophase pitch can be obtained. The advan~age of removing ~he organic solvent-soluble components is to facilitate the formation of a mesophase by remoYing the soluble oomponents which are dificult of forming a mesophase and to obtain a pitch having high optical anisotropy and a low melting point.
The mesophase pitch is a polycyclic aroma~ic oompound in view of its chemical s~ructureO Preferably, it has a melting point of 200 to 400 C, a weight average molecular weight of 200 to 10,000 and a degree of optical anisotropy of 20 to 103 %, and contains 30 to 100 % of components insoluble in benzene, toluene, xylene or tetrahydrofuran. When the starting pitch is subjected to an operation of removing the organic solvent-soluble components, the mesophase pitch has a melting point of 200 to 350 C and a weight avera~e molecular weight of 200 to 8,000. The melting point can be determined by an ordinary capillary method in a nitrogen box ~the same hereinafter~.
The premesophase pitch can be produced by, for example, hydrogenating a petroleum or coal pitch with a hydrogen donor such as tetrahydroquinoline or hydroge-nating the pitch under hydrogen pressure in the optionalpresence of a catalyst, and then heating the resulting hydrogenated pitch for a short period of time at high temperatures under reduced pressure.
~hen the hydrogenation is carried out by using tetrahydroquinoline, at least 30 parts of the quinoline is added to 100 parts by weight of ~he pitch, and the mixture is heated at 300 to 500 C.
When hydrogenation is carried out by using hydrogen, a catalyst such as a oobalt-molybdenum system or an iron oxide system and a solvent such as quinoline are optionally added to the starting pitch, and the pitch is hydrogenated at 400 to 500 C under a partial hydrogen pressure of at least 10 kg~cm2. The resulting product is heat-treated at a temperature of at least 440 ~C under a pressure oi not more than 5~ mmHg for a period of not more than 60 minutes after optionally it is filtered and subjected to a treatment of removing th2 solvent and the light componentsO The treating time is determined by the treating ~empera~ure. Preferably7 ~he ~reatment is performed at the highest possible temperature or the shortest possible timeO ParticularlyO treatment for a time of not more than 15 minutes is ad~an~ageous.
The premesophase pitch is a polycyclic aromatic compound in view of its chemical structure~ and preferably has a melting point of 200 to 350 C and a weight average molecular weight of 600 to 6,000, and contains at least 5 % of components insoluble in quinoline~
The premesophase state, as referred to herein, denotes the state which is optically isotropic at room temperature but on heating to a high temperature of at least ~00 C, can change to a mesophase state. The premesophase pitch alone is spun, rendered infusible, and pyrolyzed, orientation occurs in the pyrolyzing step, and high modulus fibers can be obtained in the same way as in the case of using a mesophase pitch~ The advantage of using the premesophase pitch is that it can be spun at lower temperatures than when the mesophase pitch is used.
The pitch in the latently anisotropic state can be obtained by removing light fractions from a heavy oil (to be referred to sometimes as the FCC slurry oil~
obtained by fluidi~ed catalytic cracking of petroleums, heat-treating the resulting pitch at 300 to 500 C, and subjecting the resulting optically anisotropic mesophase pitch to a hydrogenation treatment until the mesophase contained therein changes into substantially quinoline-soluble componen~s and the pi~ch as a whole forms anoptically isotropic homo~eneous phase.
Various known methods used for hydrogenation of the aromatic ring may be used in the hydrogenation. For example~ there can be used a method involving reduction with an alkali metal, an alkaline earth metal and a compound of any of these~ an electrolytic reduction method, a hydrogenation method in a homogeneous system with a complex compound catalyst, a hydrogenation method in a heterogeneous system using a solid catalyst, a hydrogenation method under a hydrogen pressure in the absence of catalyst, and a hydrogenation method using a hydrogen donor such as tetralin.
The hydrogenation may be carried out at a temperature of not more than 400 C under a pressure of not more than 200 atmospheres, although these conditions may vary depending upon the method used. The resulting hydrogenated pitch may be maintained in the heat-melted state to enhance its thermal stability.
The heating temperature at this time is pre-ferably above the melting temperature but does not exceed 450 C. Heating at high temperatures may result in the formation of a new mesophase~ The formation of too large an amount of the mesophase is undesirable because it increases the softening point of the pitch~
The pitch in the latently anisotropic state is a polycyclic aromatic compound in view of its chemical structure. Preferably, it has a melting point of 200 to 350 C and a weight average molecular weight of 200 to 6,000, and is soluble in quinoline.
The latent anisotropy, as used herein, denotes anisotropy which is attributed to the orientation of molecules in the direction of an external force such as a shearing force or a stretching force, which occurs upon application of the external force. For example, when this pitch is spun, rendered infusible ~cured~ and ~g ~

pyrolyzed in accoLdance with an ordinary method of pro-ducing pitch-type carbon fibers, fibers oriented in the direction of the fiber axis are obtained~
The pitches in the mesophase~ premesophase or the latently anisotropic state may be used singly or in combination.
These pitches and the reaction product between the organic silicon polymer and the optically isotropic pitch, are melted at a temperature in the range of 200 to 500 C. The pitch in the mesophaseY premesophase or the latently anisotropic state is used in a proportion of 5 to 50,000 parts by weight9 preferably 5 to 10,000 parts by weight, per lOQ parts by weight of ~he reaction pro-ducto If the proportion of the pitch is less than 5 parts by weight, highly elastic pyrolyzed fibers are dif-ficult to produce as a final produc~. If it exceeds 50,000 parts by weight, it is difficult to obtain final fibers having excellent wettability with respect to the matrix and excellent oxidation resistance.
Thus~ according to this invention, there is provided a polymer composition, comprising (A) an organic silicon polymer, (B) a polycyclic aromatic compound in the mesophase, and (C) an optically isotropic polycyclic aromatic compound, at least a part of component (A) being chemically bound to component (Bl and~or component (C) by reaction. The formation of a chemical bond can be deter-mined by the increase of the amount of that portion of the polymer composition which is insoluble in, ~or exampler toluene over the total amount of toluene-insoluble portions of the individual components. For example, if the polymer composition comprises 1 part by weight of the reaction product obtained between 30 parts by weight of the organic silicon polymer (A~ and 70 parts by weight of component tC), and 14 parts of component (B), the amount of the insoluble portion of the polymer ~ ,`,~?~,r~

composition increases to about ].03 to 1~03 time based on the total amount oE the insoluble portic)ns of the indiYidual componentsO Generally~ this figure tends to be larger as the total amcunt oi- components SA~ and (C~
bcomes larger than the amount oi component (B~ and the proportion of COmpOJlent (A~ becomes larger in the total amount of components (A) and (C)O
The polymer composition of this invention is composed of the constituents (A~, ~s3 and (C)~ and at leasS a part of tlle silicon atoms o component (A) is bonded to tlle carbon atoms on the aromatic rings of component ~B~ and~or component (C)O Preferably, the weight ratio of of component (A) to the total amount of components (B) and ~C~ is from 1:0~5 - 5,000, and the weight ratio of component ~B) to component (C~ is 1-0~02 - ~.
If the weight ratio of of component (A) to the total amount of components (B) and ~C) is below 0.5, the amount of the mesophase component in the polymer com-position is insufficient, and fibers obtained from thepolymer composition have low strength and modulus of elasticity. If this ratio exceeds 5~000, the amount of the organic silicon in the polymer composition is in-sufficient, and fibers obtained from this composition have lowered oxidation resistance and tend to have reduced wettability with an FRP matrix.
If the weight raito of (C) to tB~ is less than O oO2 ~ the polymer composition has reduced spinnability in melt spinning, and its spinning becomes extremely dif-ficult with the occurrence of fiber breakage owing to thenon-uniform viscosity of the spinning dope~ If the above weight ratio exceeds 4, the amount of the mesophase component in the polymer composition becomes insufficient, and fibers obtained from the composition have lowered strength and modulus.
The polymer composition of this invention ~6~

cont~ins 0.01 to 30 % by weight of silicon atoms, and has a weight average molecular weigh~ of 200 to 11,000 and a melting point of 200 to 400 C.
If the silicon atom content of the polymer composition is less than 0~01 %, the amount of the amor-phous phase composed of Si 9 C and O or the ultrafine beta-SiC particles in the fibers formed from the com-position is too small, and therefore~ no marked im-provement in the wettability of the resulting fibers ~ith respect to the FRP matrix and the oxidation resistance of the fibers is achieved. On the other hand, if the silicon atom content exceeds 30 %~ the high elasticity of the fibers owing to the orientation of ultrafine graphite crystals in the fibers and the improved heat resistance of the fibers in a non-oxidizing atmopshere cannot be achieved~ and the resulting fibers do not at all differ from SiC fibers.
If the weight average molecular weight of the polymer composition is lower than 200, the composition does not substantially contain a mesophase. From such a composition, thereforei highly elastic fibers cannot be obtained. If its weight average molecular weight is larger than 11,000, the composition has a high melting point and becomes difficult to spin.
A polymer composition having a melting point lower than 200 C does not substantially contain a meso-phase, and as-spun fibers from this composition tend to melt adhere at the time of curing, pyrolyzed fibers having high strength and modulus of elasticity cannot be cbtained. If it is higher than 400 C, the composition is decomposed during spinning, and becomes difficult to spin.
Preferably, the polymer composition contains 10 to 98 ~ of components insoluble in an organic solvent such as benzene, toluener xylene and tetrahydrofuran and has a degree of optical anisotropy at room temperature of 5 to 97 %~

If the proportion of the organic solvent-insoluble portion of the polymer composition is less than 10 ~, or the degree of optical anisotropy of the composi-tion is less than 5 %, the mesophase is hardly oriented in the direction of the fiber axis at the time of melt-spinning the composition. Hence, even when the resulting as-spun fibers are cured and pyrolyzed, there can only be obtained fibers having low strength and low modulus of elastiGity. When the composition contains more than 98 % of the organic solvent-insoluble portion or has a degree of optical anisotropy of more than 97 %, the amount of the mesophase in the composition becomes too large, and the composition becomes difficult to spin.
To produce the first fibers of this invention from the polymer composition of this invention, a spin-ning dope of the polymer composition is preparedl and spun, and the resulting as-spun fibers are cured under tension or under no tensionO The resulting infusible fibers are pyrolyzed in an inert gaseous atmosphere at a te~perature of 800 to 3,000 C.
The spinning dope is prepared usually by heat-melting the polymer composition and as required, filter-ing the melt to remove substances detrimental to spin-ning~ such as microgels or impurities. Its spinning is carried out by an ordinarily used synthetic resin spinning apparatusO
The temperature of the spinning dope to be spun is advantageously 220 to 4~0 C although it varies de-pending upon the softening temperature of the starting composition.
As required, a spinning cylinder is mounted on the spinning appratus, and the atmosphere of the inside of the spinning cylinder is formed into an atmosphere of at least one gas selected from air, an inert gas, hot air, a hot inert gas, steam and ammonia gas, and by increasing the wind up speed, fibers having a small diameter can be obt~inedO The spinning speed in melt spinning can be varied within the range ~ 50 to 5,000 m/min. depending upon the properties of the starting composition.
The re~ulting as spun fi~ers are then reduced infusible Scuredi under tension or under no tension.
A typical method of curing is to heat the as-spun ribers in an oxidizing atmosphere~ The tem-perature at this time is preferably 5Q to 4~0 CO If the temperature i5 excessively low, no bridging ~akes place in the polymer constituting the as-spun fibers. If this temperature i5 exCeBSively high, the polymer burns.
The purpose of curing is to bridge the polymer constituting the as-spun fibers ~o proYide an insoluble 1~ and in~usible three dimensional structure and to preYent it from being melted with the adjacent fibers melt-adhering to each other in the subsequent pyrolyzing step~
The gas constituting the oxidizing atmosphere at the time of curing is pr~ferably, for example, air~ ozone, oxygen, chlorine ga~, bromine gas, ammonia gas or a gaseous mixture of these~
Another method of curing comprises applying gamma~ray irradiation or electron beam irradiation to the as-spun fibers in an oxidizing or non-oxidizing atmos-phere optionally with heating at low temperatures.
The purpose of applying gamma-rays or electron beam irradiation is to polymerize the polymer forming the as-spun fibers to a greater degree, and thereby prevent the as-spun fibers from melting and thus losing the fiber shape.
The suitable irradiation dose of ~amma-rays or electron beams is 106 to 101 rads.
The irradiation may be carried out under vacuum or in an atmosphere of an inert ga~ or an oxidizing gas such as air, ozone, oxygen, chlorine gas, bromine gas~
ammonia gas or a gaseous mixture thereof.

f ~ r ~

~~ 17 ~
The operation of curing may be carried out under tension or under no tension. The tension to be applied is preferably 1 to 500 g/mm2~ Application of a tension o~ not more than 1 9/mm2 cannot keep the fibers taut. On the other hand, when this operation is carried out under no tension, the as-spun fibers assume a wavy form because of their shrinkage, but since this can Erequently be corrected in the subsequent curing step, tension is not always essential.
The resulting infusible fibers are pyrolyæed in vacuum or in an atmosphere of an inert gas at a temp~ra-ture of 800 to 3~0~0 C. The pyrolyzing can be carried out under tension or under no tension. Preerably, it is carried out under tension because if the fibers are pyrolyzed at high temperatures under a tension of, for example, 0.001 to 100 kg/mm2, inorganic fibers having high strength and little flex can be obtained.
It is presumed that in the temperature elevat-ing process, carbonization begins to become vigorous at about 700 C, and is almost completed at about 800 C.
To obtain higher temperatures than 3,000 C, an expensive apparatus is required, and there is no industrial advant-age. Hence, pyrolyzing is carried out at a temperature ~f ~00 to 3,0~0 C.
Thus, according to this invention, there are provided high strength and high modulus fibers containing components ~i), (ii) and (iii) as stated at the outset of the section ~Disclosure of the Invention" are obtained.
Component (i) is crystalline carbon oriented substantially in the direction of the fiber axis. It is believed in relation to the production process described above that this carbon is derived from a polycyclic aromatic compound which is in the mesophase, or in other words, optically anisotropic.
Owing to the presence of component (i), a structure known in the art, that is, a radial structure, an onion structure, a random structure, a core-radial structure~ a skin onion structure or a mosaic structure is observed in the c~vss section of the fibers of this inventionO
Component (ii) is amorphous carbon and/or crystalline carbon oriented in a direction different from the fiber axis direction. Like~wise, in relation to the production process described above, this component is believed to be derived from an optically isotropic poly~
cyclic aromatic compound.
Crystalline carbon has a crystallite size of not more than 500 angstrom, and is ~n ultrafine graphite crystal oriented in the direction of the fiber axis in which by a high-resolution electron microscope having a resolution ability of 1.5 angstrom, a fine lattice image corresponding to ~002) plane with an interplanar spacing of 3.2 angstrom.
In the fibers of this invention~ microcrystals which are three-dimensionally arranged with a small interlayer distance are effectively formed.
The silicon-containing component tiii) con-sisting essentially of silicon, carbon and oxygen may be an amorphous phase or an aggregation of a crystalline particulate phase consisting essentially of crystalline SiC and an amorphous SiOx (O<x<2) phase.
The crystalline particulate phase consisting essentially of crystalline SiC may have a particle diameter of not more than 500 angstrom.
The distributed state of silicon in the fibers can be controlled in relation to the atmosphere in which fibers are pyrolyzed for production of fibers, the size and concentration of the mesophase in the starting material. For example, if the mesophase is grown to a large size, the silicon-containing polymer is liable to be pushed out onto the fiber surface layer, and after pyrolyxing, forms a silicon rich layer on the fiber surface.

The fibers of this invention preferably contain 00015 to 200 parts by weight of component ~ per 100 parts by weight of components (i) and (iii) combined, and the weight ratio of component ~i~ to component (ii) is 1:0~02 ~ ~.
If the proportion of component (iii~ is less than 0~015 part by weigh~. per 100 parts by weight of components (i) and ~ combined~ the resulting fibers are much the same as pitch fibers, and an improvement in oxidation resistance and wettabili~y canno~ be expec~ed~
If the proportion exceeds 200 parts hy weight, fine crystals of graphite are not effectively formed, and ibers of a high modulus of elasticity are difficult to obtain~
lS The fibers of this lnvention ~omprises pre-ferably 0.01 to 29 % by weight of silicon, 70 to 93.9 by weight of carbon and 0.001 to 10 % by weight of oxygen, especially preferably 0.1 to 25 ~ by weight of silicon, 74 to 99~8 % by weight of carbon and 0.01 to 8 %
by weight of oxygen, based on the total weight of silicon, carbon and oxygen.
As second fibers of this invention, the present invention provides fibers having high strength and high modulus comprising (i) crystalline carbon oriented substantially in the direction of the fiber axis, 5ii) amorphous carbon and/or crystalline carbon or.iented in a direction different from the direction of the fiber axis, and (iii') a silicon-containing component sub-stantially composed of 0.5 to 45 ~ by weight of a metal selected from titanium, ~irconium and hafnium, 5 to 70 %
by weight of Si, 20 to 40 % by we.ight of C and 0.01 to 30 % by weight of O, the proportions being based on the total weight of said metal, silicon~ carbon and oxygen.
According to this invention~ the second fibers ~3~ t~

of this invention can be pro~uced by a process which comprise6 preparing a spinnins dope of a polymer com-position comprising tA') an organic silicon polymer resulting from random bonding of a plurali~y of units of at least one kind select.ed from the group consisting o units of the following formula ~a) -Si~ ... (a) wherein Rl and R2, independently from each other/ represent a hydrogen atGm~ a lower alkyl group, a phenyl group or a silyl group ~-SiH3~, and at least one unit of formula (b) -Si- ... (b) R

wherein Rl is as defined abover and R3 re-presents -M or -OM, and M represents one equiva-lent of a metal selected from the group con-sisting of titaniuum, zirconium and hafnium, via methylene groups (-CH2-) or both via methylene groups or directly, (B) a polycyclic aromatic compound in the mesophase, premesophase or the latently anisotropic phase, and (C) an optically isotropic polycyclic aromatic compound which is not in the premesophase or the latently anisotropic phase, part of component (A~ being chemically bonded to com-ponent ~B) and~or component (C);

spi.nnitlg the spinning dope, rendering ~he ~ibe~s infusible under tension or under rlo tel-sion; and pyrol~zin~ the resul~ing infusible ~ibers in va~uum or in an atmosphere o~ an .inert gas at a tem-perature of 800 to 3,000 CO
The polymer compos.ition used in the spinning step has been provide~ for the fir5~ time by ~he present inventors and constitute part of the present invention.
The novel polymer composl~ion can be produced by heating the organic silicon polymer (~) described above in the production of ~he firs~ ~ibers of the invention (to be sometimes referred to as the first organic silicon polymer) and an optically isotropic pitch 1~ in an inert gas at a te~perature of preferably 250 to 500 C, then reacting the reaction product with a transition metal compound of formula MlX4 wherein Ml represents titanium, zironium or hafnium, and X may be any moietyp for example a halogen atom, an alkoxy group~ or a chain forming group such as a beta~diket.one! which permits M to be bonded to the silicons of the precursor reaction product directly or through an oxygen atom by condensation, at a temperature oX 100 to S00 C; and heat-melting the reaction product with a pitch in the mesophase, the premesophase or the latently anisotropic state at a temperature of 300 to 500 C.
The first organic silicon polymer/ the op~ically isotropoic pitch and the heating condition~
therefor are as described hereinabove.
The precursor reaction product obtained by heating is then reacted with the transition metal - ~2 -csmpound MlX4. By this reaction, the silicon atoms of the precursor reaction product may be at least partly bonded to the me~al M directly or through an oxygen atom.
If the reaction temperature is low, the con-S densation reaction between the precursor reaction productand the compound of formula MlX4 does not proceed. If the reaction temperature is excessively high, the cross~
linking reaction through M proceeds excessively to cause gellation or the precursor reaction product itself con-denses and becomes high in molecular weight. In somecases~ MX4 volatilizes, and a composition for obtaining excellent fibers cannot be obtained.
The reaction product can also be prepared by reacting the reaction product obtained after the reaction f the organic silicon polymer (A) with the transition metal compound, with a pitch.
The above reaction product contains the organic silicon polymer (A') which results from random bonding of a plurality of the units represented by formula (a) to at least one unit of formula (b) through methylene groups or both through methylene groups and directly without the intermediary of methylene groups.
The units of formula (b~ may be~ for e~ample, as follows when Ti(OC4Hg)4 is used as the transition metal CompoundO
Rl Rl -Si- and -Si-%Ti 0%Ti The reaction temperature at this time is especially desirably 200 to 400 C.
The reaction product obtained by the above reaction is then heat-melted with a pi.tch in the meso-phase, premesophase or the latent anisotropy.
It should be understood that as regards these 3 ~ ¢

pitches and l:he heat-rlle:lt.ing condltion~ he same descrip~ion as ~ha~ ror ~he polymer composil:ion used in the produc:t.ion vf the first ib~ers ~to be sometimes referred to as the firc;t polymer COJllpO~iitiO~13 will applyO
The above polymer comlposition Ito ~2 somet:imes referred to as the transition metal~conta.ining reaction pros]uct or the second polymer composi~ionj may also be produced by a process which comprises reacting the irst organic silicon polyllner (Aj with an optically isotropic 1~ pitch, and reactirlg the resulting product wi~h a pol3r-s:yclic aromatic compound such as one in ~he mesophase and a transition metal compourld successively or together~
Thus9 accordin~ to this inventior;~ there is provided a polymer composition comprising ~A' ) an organic sil.ic3n compound, (B) a polycyclic aromatic compound sus~h as one in the mesophase~ and (C~ an optically isotropic polycyc~ic aromatic compound, at least part of the com-ponent (A') being chemically bonded to component ~B) and/or component (C).
The second polymer composi~cion of this invention co~prises the components (A')~ (B) and ~C), and the silicon atoms of the component (A') are at least partly bonded to the carbon atoms of the aromatic rings of component ~B) and/or component (C). The weight ratio of component ~A') to the total sum of components (~) and tC) is preferably 1:0~5 - 5~000r and the weight ratio of eomponent (C) to component (B) is preferably 1:0~02 - 4O
I the weight .ratio of componen~ ~A') to the total sum of components (B) and (C) is less than 0.5, the amount of the mesophase component in the second polymer composition is insufficient, and ibers obtained from this polymer have low strength and ~odulus of elasticity.
I~ this ratio exceeds 5,000, the amount of the organie silicon compound in the second polymer composition becomes insufficient, and fibers obtained f rom this polymer have low oxidation resistance. Furthermore, the -- 2~ -wettability of the fibers with respect to an FRP matrix :ellds t~ be lowO
Xf the weight ratio of ~C~ ~o (B) is less than O oO2 ~ the spinnability o:E the slecond polymer composition 5 in its melt~spirlrling is ~egradeld~ and f iber breakage occurs o~ing to the norl-unifor~n viscosity of the dope.
Herlce~ the polymer composition becomes extremely dif-ficult to spinO If 'che above weight ratio Zexoeeds 4,, the amount o the ~esophase component i n the second polymer composition is insllE:Lc.ient, and fibers obtained from the polymer tends l:o have low s~rength and modulus of elas-ticity O
Preferably7 in component IA' ~ 7 tbe ratio of the total number of units Si-CH2 to that of units Si-Si is 15 ~ri'chin 1 0 - 20, and 0.2 to 35 ~ o units M of the tran sition metal compound is contained based OS! the total w@ight of the units Si~CH2 and units 5i Si.
The second polymer co~position preferably contains 0 oOl to 30 %, especially O.OS ~o 30 %, of silicon atoms, and 0,005 to 10 % of M, and has a weight average molecular weight of 200 to 11,000 and a m21ting point of 200 to 400 C.
If the content of silicon atoms in the second polymer composition is less than 0~01 %, the wettability Of the resulting fibers with respect to an FRP matrix and the oxidation resistance of the fibers do not markedly show an improvement~ On the other hand, i it exceeds 30 %, the orientation of the ultrafine graphite crystals in the fibers makes it impossible to achieve high elasticity in the fibers, and an improvement in the heat resistance of the fibers in a non-oxidizing atmosphere, and the fibers do not differ at all from 5iC fibersO
Since the second polymer composition contains M
in addition to silicon, the composition shows a further improvement in mechanical properties, wettability wîth plastics~ If the content af M is less than 0.005 %~ the above properties are searcely exhibited. If it exceeds 10 %~ both a high-melting product which is extremely crosslinked and the unreacted MX~ exist in the com-position, and it becomes very dlifficult to melt-spin a dope of th~ composition.
If the second polymer composition has a weight average molecular weight lower than 200, it hardly con-tains a rnesophase~ and therefore, high elasticity fibers cannot obtained f rom the composition~ If its weight 10 average molecular weight is larger than 11,000~ the composition has a high melting point and is difficult ~o spin.
If the second polymer composition has a melting point lower than 2û0 C, it does no~ subs~antially con-tain a mesophase, and as-spun fibers obtained by spinning this composition are liable to melt-adhere when subjec~ed tG curing. Thus, fibers having high strength and modulus of elasticity cannot be obtained. If its mel~ing point is higher than 400 C, the composition undergoes de-compositon during spinning, and is difficult to spin.
Preferably, the second polymer composi~ioncontains 10 to 98 % of a portion insoluble in an organic solvent such as benzene, toluene, xylene or tetrahydro-furan, and has a degree of optical anisotropy at room temperature of 5 to 97 ~.
If the proportion of the organic solvent-in~oluble portion of the second compoqition is less than 10 % or its degree of optical anisotropy is less than 5 %, the meqophase is hardly oriented in the direction of the fiber axis when the composition is melt-spun. Accord-ingly~ when the as-spun fibers are cured and pyrolyzed, there can only be obtained fibers having low strength and modulus of elasticity. On the other hand, when the second poly~er composition contains more than 98 % of the organic solvent-soluble portion, or has a degree of optical anisotropy of more than 97 ~, the amount of the ~s ~

mesophase in the composition be~com~s ex~essive, and the composi ti on i s di f f icu 1 t tQ spi n O
The secolld f ibers may be produced f rom the second polymer composition of this invention by quite the 5 same process a5 that for producing the first fibers of thi s i nverl~i on .
Thus7 the present invention also provides fibers of high strength and elasticity comprising com-ponents (i), ~ii) and (iii') described aboYe~
The component (i) is crystalline carbon oriented substantially in the direction of the fiber axis. In relation to the above production process, ~his component is believed to be derived f rom a polycyclio aromatic compound in the mesophase, or in other words, an optically anisotropic polycyclic aromatic compound. In the fibers of this invention, a structure well known in the art is observed in a iber cross-section owing to the presence of component (i~, namely a radical struc~ure, an onion structure, a random structure, a core-radial struc-ture, a skin onion structure, or a mosaic structure.
The constituent component (ii~ is amorphouscarbon and/or crystalline carbon oriented in a direction different from the direction of the fiber axis~ Like-wise, in relation to the above production process, it is believed that component Sii3 is derived from an optically isotropic polycyclic aromatic compound.
The crystalline carbon has a crystallite size of not more than 500 angstrom. It is in the form of ultrafine graphite crystal particles in which under a high-resolution electron microscope, a fine lattice image corresponding to (002) plane having a planar spacing of 32 angstrom and oriented in the direction of the fiber axis is observed.
In the fibers of this invention, microcrystals having a small in~erlayer distance and arranged three dimensionally are effectively formed.

The silicon~contain.ing component ~iii') con-sisting essentially of the transition metal, silicon, carbon and oxygen may be an amorphous phase, or an ag-gregate consisting substantially of a crystalline fine particulate phase consisting of silicon~ carbon and a transition metal selected from the group consisting of titanium, zirconium and hafnium and an amorphous SiOy (0<y<2~ and MOz (M is Ti, Zr or Hf, and 0~z<2~.
The amorphous phase of the silicon-containing component tends to form when the pyrolyzing temperature .in the production of the fibers is lower than 1000 C.
The aggregate of the crystalline fine particulate phase and the amorphous phase tends to form when the pyrolyzing temperature is 1700 ~ or higher.
The crystalline fine particulate phase consists of crystalline SiC, MC (M is as defined above), a cry-stalline solid solution of SiC and MC, and MCl x ~D<x~l), and may have a particle diameter of not more than 500 angstrom.
At pyrolyzing temperatures intermediate between the above temperatures, a mixture of the aggregates forms. The amount of oxygen in the fibers can be con-trolled by the proportion of MX4 added or the curing conditions.
The state of distribution of the component (iii') may also be controlled by the atmosphere of pyrolyzing, or the size and concentration of the meso-phase in the starting material. For exampleg when the mesophase is grown to a large size, the component (iii~) is liable to be pushed out onto the surface of the fibers.
Preferably, the fibers of this invention con-tain 0.015 to 200 parts by weight of component (iii) per 100 parts by weight of the components (i) and (ii) com-bined, and the ratio of components (i) to (ii) is 1 : 0 . 0 ~

If the amQunt of component (iii) is less than O.OlS part by weight per lO0 parts by weight oE com-ponents ~i) and ~ii) combined, khe resulting fibers do no differ from pitch fibers, and an improvemel1t in oxidation resistance and wettability can Tnardly be e~pectedO If the above proportion exceeds 200 parts by weight, fine crystals of graphite are not efEectively formed, and fibers having a high modulus of elasticity are difficult to obtain.
The fibers of this inven~ion preferably consist of O~Ol ~o 30 % by weight of silicon, O.Ol ~o lO % by weight of the transition metal ~Ti, Zr or Hf~, 65 to 99.9 ~ by weight of carbon, and O.OOl to lO % by weight of oxygen, particularly preferably O.l to 25 % by weight 15 of silicon, 0.01 to 8 % by weight of the transition metal, 74 to 99.8 % by weight of carbon~ and OoOl to 8 by weight of oxygen.
The first and second fibers may be advantage-ously used as a reinforcing material for composite materials. Examples of such composite materials are as follows:-tl) A fiber-reinforced composite material comprising a plastic as a matrix.

(2) A fibee-reinforced composite material comprising ceramics as a matrix.
~ 3) A fiber-reinforced composite material comprising carbon as a matrix.
(4) A fiber-reinforced composi~e material comprising a pyrolyzed product of the polymer composition ~f this invention as a matrix.
(5) A composite material comprising a metal as a matrix.
These examples will be described successively.
For the composite mater al comprising a plastic as a matrix, both the firs~ and the second fibers of the invention can be used.

- 2~
Incorporation of the fibers rnay be effected by, Eor example, a method comprising incorporating these fibers in the matrix, monoax7ally or multiax.ially, a method comprising using the fibers in the form of a woven fabric such as a plain~weave fabrlc? a satin weave fabric, a twill fabricF an imitation gauze fabric, a helical weave fabric and a three-dimensionally woven fabric, or a method comprising using the fibers as chopped fibers.
Examples of the plastic include epoxy re~ins~
unsaturated polyester resins, phenolic resins, polyimide resinsp polyurethane resins~ polyamide resins, poly-carbonate resins, silicone resins, fluorine-containing resins, nylon resins, polyphenylene sulfide resins, polybutylene terephthalate, ultrahigh-molecular-weight polyethylene, polypropylene, modified polyphenylene oxide resins, polystyrene, ABS resins, vinyl chloride resins, polyether-ether ketone resins and bismaleimide resinsO
These plastic composite materials can be pro-duced by methods known E~ se, for example, tl) a handlayup method, (2) a matched metal die method, (3) a break away method, ~4) a filament winding method, (5) a hot press method, (6) an autoclave method, and (7) a con-tinuous pulling method.
According to the hand layup method (1), the fibers are cut and spread densely on a mold. Then~ the plastic containing a catalyst is coated on the spread fibe~s ~y means of a bru~h or a roller and allowed to cure naturally. The mold is then removed to produce a composite material.
According to the matched me~al die method ~2), the fibers are impregnated with the plastic, a curing agent, a filler and a thickening agent, and then molded under heat and pressure to form a composite material.
Depending upon the form of the material during the molding, either the SMC (~heet molding compound) method 1 r~
~ 30 ~
or the BMC ~bulk molding compound1 method may be selected.
According to the break away method (3)~ sheets of the fibers are impreqna~ed wi~h the plastic and pre--cured to form prepregs. The prepregs are wound up arounda tapered mandrel, and after curing, the cured composite material i5 pulled out~ A hollow article of a complex shape can be produced by ~his methodO
According to the filament winding methed ~4), inorganic fibers impregnated with a thermose~tinq resin such as an epoxy resin or an unsaturated polyester resin, wound around a mandrel, and treated to cure the resin.
The cured product was removed from the mandrel to fsrm a composite material~ This method is carried out by a wet procedure or a dry procedure ~using a prepreg tape).
According to the hot press method ~5), prepreg sheets of the fibers are stacked in one direction or at any desired angle, and the stack i5 heated under pressure by a hot press to form a composite material in the form f a plate.
According to the autoclave method (6), prepregs are stacked on a mold, and wrapped with a special rubber.
In a vacuum condition, the stack is put in a high-pressure kettle and heated under pressure to obtain a cured composite material. This method is suitable for production of complex shapes.
According to the continuous pulling method (7~, the fibers and the plastic are separately fed into a molding machine, and mixed just before a mold. On the 3~ way, the mixture is passed ~hrough a heating oven, and continuously ~aken up as a continuous long composite material.
The tensile strength (~c) of the composite material produced from the fibers and the plastic matrix is expressed by the following equation.

~c = ~fVf ~ ~MVM

In which ~c the tensile strength of the composite material ~ f: the tensile strength of the fibers M^ the tensile strength of the matrix Vf: the volume percent of the fibers VM: ~he volume percent of ~he matrix ~s shown by the above equation, the strength Qf the composite material becomes larger as the volume per-centage of the fibers in the composite material becomes larger. Accordingly to produce a composite material having high strength, the proportion of the volume of the inorganic fibers to be combined must be increased.
However, if the volume proportion of the inorganic fibers exceeds 80 ~, the amount of the plastic matrix corres-pondingly decreases, and it is impossible to fill the interstices of the hybrid fibers sufficiently with the plastic matrix. As a result, the composite material 20 produced does not exhibit the strength shown by the above equation. If ~he volume proportion of the fibers is decreased, the strength of the composite material cor respondingly decreases as shown by the above equation.
To produce a practical composite material, it is 25 necessary to combine at least 10 % of the fibers. In the production of fiber-reinforced plastic composite materials, the volume proportion of the fibers to be combined is preferably 10 to 80 %, especially preferably 30 to 60 ~.
The various mechanical properties in the pre-sent specification are determined by the following measuring methods.
(a) Interlayer shear strength In the testing method for determining inter-35 layer shear stress, a composite material containing fibers ~10 x 12 x 2 mm) oriented monoaxially is placed on two pins ~length 20 mm~ having a radius of curvature of Ç mmO By using a presser with its tip having a radius of curvature of 3OS mm, the composite material was compres-sed and the so-called 3 point bending test was carried out, ancl its interlayer shear stress is measured, and expressed as shear stress ~kg/n~m2~.
(b) Tensile strength and tensile modulus in a direction perpendicular ~o the fibers A composite material, 2 mm ~hick, reinforced monoaxially with fiber~ was produced~ and a test piece, 19 x 127 mm, was taken from it 50 that the axial direc-tion of ~he test piece became perpendicular to the direction of the fiber arrangement. The test piece had a thickness of 2 mm. A curvature of 125 mmR was provided in the thickness direction at the centeral portion of the test piece was finished in a thickness o~ about 1 ~m.
The pulling speed was 1 mm/min., and the tensile strength (kg/mm2) and tensile modulus (t/mm2) were determined.
(c~ Flexural strength and flexural modulus in a direction perpendicular to the fibers A composite material, 2 mm thick, reinforced monoaxially with fibers was produced, and a test piece, 12.7 x 85 mm, was taken from it so tbat the axial direc-tion of the test piece became perpendicular to the direction of the fiber arrangement. The test piece had a thickne~s of 2 mm. A curvature of 125 mmR was provided in the thickness direction at the centeral portion of the test piece was finished in a thickness of about 1 mm.
The test piece is subjected to a 3-point bending tes~, and the flexural strength (kg/mm2) and the flexural modulus (t~mm~) are determined.
The interlayer shear strength, the tensile strength in the direction perpendicular to the fibers and the flexural strength in the direction perpendicular ts the fibers are indices showing the strength of ~onding between the matrix and the fibers.

~ 3~

(d~ Tensile strength and tensile modulus A composite material, 2 mm thick, reinforced monoaxially with fibers was produced, and a test piece, 12.7 x 85 mm, was taken from it so that the axial direc-tion of the test piece became perpendicular to thedirection of the fiber arrangementO ~he test piece had a thickness of 2 mm. A curvature of l25 mmR was provided in the thickness direction at the centeral portion of the test piece was finished in a thickness of about 1 mmO
The pulling speed was 1 mm/min., and the tensile strength (kg~mm2) and tensile modulus (t/mm2~ were determined.
~e) Flexural strength and 1exural modulus A composite material, 2 mm thick, reinforced monoaxially with fibers was produced, and a test piece, 12~7 x 85 mm, was ~aken from it so that the axial direc-tion of the test piece became perpendicular to the direction of ~he fiber arrangement. The test piece had a thickness of 2 mm. A curvature of 125 mmR was provided in the thickness direction at the centeral portion of the test piece was finished in a thickness of about 1 mm.
The test piece was subjected to a 3-point bending test, and the flexural strength (kg/mm2) and the flexural modulus (t/mm2) were determined.
(ft Flexural impact value Flexural impact value was measured by the Charpy testing method (JIS R7111) by three-point bending.
The result wa~ expressed by flexural impact value (kg-cm/
cm2) The flexural impact value is an index repre-senting the strength of bonding between the plastic and the fibers, particularly an index representing the strength of resistance to instantaneous impact. If the flexural impact value is low, the resin is liable to separate from ~he fibers, and destruction is liable to occur owing to instantaneous impact.
The above plastic composite material has a~ an in~erlayer shear ~trength oE at least 8.5 k9JMm 9 b~ a tensile ~trength in a direction perpen-dicular to the fibers of at least 6 kg/mm~
c) a flexural modulus in a direction perpen-dicular to the fibers of at least 8 kg/mm2, and d~ a flexural impact va:lue of at least 200 kg-cm/cm2.
Since the fibers of this inYention have ex-cellent wetting property with respect to the plastics, the fiber-reinforced plastic composite material sf this invention does not particularly require surface-treatment of the fibers and has excellent strength of bonding between the fibers and the plasticO Accordingly, the present invention provides a composite material having excellent interlayer shear strengtht tensile strength in a direction perendicular to the fibers, a flexural strength in a direction perpendicular to the fibers, and flexural impact value.
Since the fibers of this invention contain carbon in which the crystals are oriented, they have higher elasticity than amorphous inorganic fibers.
Accordingly, plastic composite materials reinforced with the fibers of this invention have excellent tensile modulus and flexural modulus~
The fibers of this invention are produced at lower costs than conventional silicon carbide fibers because the use of an expensive organic silicon compound i.s decreased.
The fibers of this invention have an excellent reinforcing effect in plastic composite materials. The resulting reinforced plastic compssite materials have excellent mechanical properties and can withstand in a severe environment over long periods of time. Hence, they can be used in ap~licat.ions in which conventional inorganic fiber-reinforced plastic composite materials ir~

cannot be used satisfactorily. ~or example, such rein-f~rced materials can be used as building materials, materials for aircraft and space exploiting devices, materials for ships and boatsS materials for land transpor~ation machines and devices~ and materials for acoustic machines and devices.
The first or second fibers of the invention may be hybridized with fibers selected from the group con-sisting of the fibers of the invention, carbon fibers, glass fibers, boron fibers, alumina fibers, silicon nitride fibers, aramid fibers, silicon carbide fibers, silicon carbide fibers having carbon as a core and Si-M-C-~ fibers (M=Ti or Zr3 having carbon as a core, and the resulting hybrid fibers may be used to reinforce plastic composite materials. The proportion of the fibers of this invention in the hybrid fibers is at least 10 %, preferably at least 20 %. If the proportion is lower than 10 ~, the hybrid fibers have a reduced im-proving effect in respect of the strength of bonding 2~ between the fibers and the plastic~ the reinforcing efficiency or the mechanical properties such as fatigue strength. In other words, the hybrid fibers have a reduced improving effect on interlayer shear strength, flexural impact value and fatigue strength.
The states of hybridization of the hybrid fibers are ~1) interhybridization achieved by lamination of a layer of a certain kind of fibers and a layer of another kind of fibers, and (2) interlayer hybridization achieved by hybridization within one layer, which are basic~ and there are ~3) combinations of these. The main combina-tions are of the following 6 types.
(a) Lamination of single layer tapes (alternate lamination of layers of dissimilar fibers) ~ b) Sandwich-type (lamination of dissimilar layers in a sandwich form) (c) Rib reinforcement (d) Lamination of mix-wover1 tows (hybridization of dissimilar monofilaments) (e) Lamination of mix~woven tapes ~hybridiza--tion of dissimilar yarns within a layer~
~f) Mix woven surface layer Plas~ic composi~e ma1:erials reinforced with these hybrid fibers have the same excellent advantages as the above-described composite materials.
Fiber-reinforced composite materials including ceramics as a matrix:
~ sth the first and second fibers of this invention described above may be used as the reinforcing fibers.
These fibers may be directly oriented in the monoaxial or multiaxial directions in the matrix.
Alternatively, they may be used as woven fabrics such as a plain weave fabric, a satin weave fabric, an imitation gauze fabric~ a twill fabric, a helical weave fabric, or a three-dimensionally woven fabric, or in the form of chopped fibers.
Carbides, nitrides, oxides~ or glass ceramics, for example, may be conveniently used as the ceramics.
Examples of the carbide ceramics that can be used include silicon carbide, titanium carbide, zirconium carbide, vanadium carbide, niobium carbide, tantalum carbide, boron carbide, chromium carbide~ tungsten carbide and molybdenum carbide. Examples of the nitride ceramics are silicon nitride, titanium nitride, zirconium nitride, vanadium nitride, niobium nitride~ tantalum nitride, boron nitride, aluminum nitride and hafnium nitride.
Examples of the oxide ceramics include alumina~ silica, magnesia, mulite and corierite. Examples of the glass ceramics are borosilicate glass, high silica glass and aluminosilicate glass. In the case of using these ceramic matrices in ~he form of a powder, the powder is advantageously as fine as possible and at most 300 micro meters in maximum particle diameter in order to better the adhesion of the ceramics to the fibers.
The proportion of the fibers of this invention mixed in the matrix is preferably 10 to 70 % by volume.
If the above mixing ratio is less than 10 % by volume, the reinforcing effects of the fibers does not appear sufficiently. If it exceeds 70 %, the amount of the ceramics is small 50 that the interstices of the fibers cannot be filled sufficiently with the ceramics.
In the production of the ceramic composite materials, it is possible to use a binder (sintering aid) for sintering the powdery ceramic matrix to a high density and/or a binder for increasing the adhesion of the powdery ceramic matrix to the fibers.
The former binder may be ordinary binders used at the time of sintering the carbide~ nitride, oxide and glass ceramics For example, boron, carbon and boron carbide may be cited as a binder for silicon carbide.
Examples of binders for silicon nitride are aluminum oxide, magnesium oxide, yttrium oxide and aluminum oxide.
Preferred examples of the latter hinder include organic silicon polymers such as diphenylsiloxane~
dimethylsiloxane, polyborodiphenylsiloxane, polyboro-dimethylsiloxane, polycarbosilane, polydimethylsilazane, polytitanocarbosilane and polyzirconocarbosilane, and organic silicon compounds such as diphenylsilanediol and hexamethyldisilazane.
The binder for increasing the adhesion of the powdery ceramic matrix to the inorganic fibers, when heated, is converted mainly into SiC or Si3N4 which reacts on the surface of the powdery ceramic matrix to form a new carbide, nitride or oxide. Consequently, the adhesion of the powdery ceramic matrix to the inorganic fibers becomes very superior. These organic silicon compounds or polymers, like the ordinary binders, act to increase the sinterability of the powdery ceramic matrix.

Accordingly~ the addition of these binder6 is very ad-vantageous to the production of composite materials having high strength. Where a strong adhesion between the powdery ceramic matrix and the fibers can be ob-tained~ it is not necessary to add binders.
The amount of the binders may be one s-uficient for producing an effect of the additionO
Usually, it is preferably 0O5 ~o 20 % by weigh~ based on ~he powdery ceramic matrix.
The ceramic composite materials reinforced with the fibers of this invention can be produced, for exmple, by the following methods.
There are various methods of obtaining ag gregates of the powdery ceramic matrix and the ibers.
The aggregate can be obtained relatively easily, par-ticularly by embedding the fibers in a rnixture sf the powdery ceramic matrix or ceramics and a binder, a method of alternatingly arranging the fibers and the powdery ceramic matrix or the above mixture, or a method com-prising arranging the fibers, and filling the intersticesof the fibers with the powdery ceramic matrix or the above mixture.
Sintering of the aggregates may be effected, for example, by a method comprising compression molding the aggregate by using a rubber press, a mold press, etc.
under a pressure of 50 to S,000 kg~cm2, and sintering the resulting molded product in a heating furnace at 800 to 2400 C, or by a method which comprises sintering the aggregate at a temperature of 800 to 2400 C by hot pressing while it was compressed under a pressure of 50 to 5,000 kg/cm2.
The above sintering methods may be carried out in an atmosphere, for example an inert gas as nitrogen, argon, carbon monoxide or hydrogen or in vacuum.
As shown in Example 102, in the production of the above fiber-reinforced ceramic composite material, a precursor of the ibers (precursor fibers before curing may be used instead of the fibers~
By subjec~ing the result:iny sintered composite ma~erial to a series of treatments to be described below at least once, a sintered body having a higher density can be obtained SpecificallyD a sintered body having a higher density can be obtained by a series of treatments o~ immersin~ the sintered body under reduced pressure in a melt of th2 organic silicon compound or polymer, or if desired, in a solution of the above compound or polymer to impregnate the melt or solution in the grAin boun-daries and pores of the sintered body, and heating the sintered ~ody after impr~gnati~n. The impregnated organic silicon eompound of polymer changes mainly into SiC or Si3N4- They exist in the brain boundaries and the pores of the composite sintered body. They reduce the cores and at the same time, form a firm bond in the ceramic matrix, and thus increases the mechanical strength of the product.
The mechanical strengh of the resulting sintered body may also be increased by coating the organic silicon compound or polymer either as such or a solution of it in an organic solvent to clog the pores, or by coating it on the surface of the sintered product 2S and then heat~treating the coated sintered body by the same method as above.
The organic solvent which may be used as required ma~ be, for example, benzene~ xylene~ hexane, ether, tetrahydrofuran, dioxane, dchloroform, methylene chloride, ligroin, petroleum ether, petroleum benzine, dime~hyl sulfoxide and dimethylformamide~ The organic silicon compound or polymer is dissolved in the organic solvent and can be used as a solution having a lower viscoci~yO
The heat-treatment is carried out at 800 to 2400 C in an atmosphere of at least one inert gas -- ~10 --selected from ni~rogn, argon and hydrogen or in vaccum.
The serie~ of impregnation or coating opera-tions may be repeated any numbe!r of times so long as these operations are possible~
In the production of the fiber-reinforced ceramic composite material, the form of the starting ceramic and the method of producing the composite are not to be limited to those described above, and ordinary forms and methods used may be employed without any in-C~nvenienceo For example, a fine powder obtained b~ the sol-gel method and a precursor polymer convertible to the ceramics by pyrolyæing may be used as the starting ceramics.
When the reinforcing fibers are short ~ibers, injection molding, extrusion molding and casting may be e~ployed as the molding method. By jointly using ~IIP (hot isostatic pressing) in pyrolyzing, the performance of the composite material may be increased. On the other hand, excellent composite materials may also be obtained by vapor-pha~e methods such as CVD and CVI.
The fracture toughness, KIC, of the ceramic composite material to that of the matrix alone containing no fibers is about 2 to 7, and the ceramic composite material has a reduction rate sf flexural strength ~to be referred to as a "flexural strength reduction rate"), measured by a thermal shock fracture resistance method, of less than ~bout 10 %.
The fracture tnughness (KIC) is measured by the IF method tIndentation Fracture ~lethod) described in J.
Am. Ceram. Soc. 59, 371, 1976) oE A~ G. EvanO
The flexural strength reduction rate is deter-mined Erom the flexural strength of a sample (obtained by heat-treating a piece, 3 x 3 x 30 mm, cut out from the ceramic composite material at a temperature of 800 to 1,300 C in air or nitrogen for 20 minutes, immediately then immersing it in water at 25 C, and then drying it) ~ 3~3~

measured by a three~point flexural strength testing method, and that oE the ceramic: composite material not subjected to the above heat-treatment~
The initial rate of f`iber degradation induced by reaction to be simply referred to as the "degradation rate" is determined as follows:
The inorganic fibers, silicon carbide fibers or alumina fibers are embedded in the po~dery cera~ic matrix and then heated in an argon atmosphere at a predetermined temperature (the temperature use~ at the time of produc-ing the composite material) for S minutes. The fibers are then takerl out, and their tensile strength is mea sured. The difference between the measured tensile strength and the tensile strength of the fibers before the treatment is divided by the heating time ~seconds)~
and the quotient i6 defined as the above "degradation rate" .
As compared with conventional ceramic composite materials reinforced with carbon fibers, the above ceramic composite material can be used at high tem-peratures in an oxidizing atmosphere. Furthermore, as compared with ceramic composite materials reinorced with other fibers, the increase of KIC in the above eeramic composite material greatly improves the inherent brit-tleness or the inherent nonuniformity of mechanicalstrength of the above ceramic composite material.
Accordingly it is suitable for use as a structural material. The improvement of high temperature impact strength enables the above ceramic matrix composite material to be used in an environment where vaeiations in temperature from high to low temperatures are great. The fibers of this invention are stable to the ceramic as a matrix, and fully achieves the inherent purpose of rein-forcement with fibers.
Fiber-reinforced composite materials including carbon as a matri~-~ oth the first and the second fibers of this invention can be used as the re!inforcing fibers.
These fibers may be dlirectly oriented in the monoaxial or multiaxial di~ections in the matrix.
Alternatively~ they may be used in woven fabrics such as a plain weave fabric~ a satin weave fabric, an imita~isn gauze fabric, a twill fabric, a helical weave fabric, or a three-dimensionally woven fabric, or in t.he form of chopped fibers.
The proportion of ~he fibers of this invention mixed in the matrix is preferably 10 to 70 ~ by volume~
If the above mixing ratio is less than 10 % by volume, the reinforcing effects of the fibers does not appear sufficiently. If it exceeds 70 %, the amount of the ceramics is small so that it is difficult to fill the interstices of the fibers sufficiently with the ceramics.
Carbonaceous material for matrices of ordinary C/C composites may be used as materials for matrices of the above composite materials. Examples include mate-rials which can be converted to carbon by pyrolyzing, forexample, thermosetting resins such as phenolic resins and furan resin, and thermoplastic polymers such as pitch, moldable materials such as carbon powder or a mixture of carbon powder and the above resins. When carbon powder 25 is used as a carbonaceous material for matrix, the use of a binder is more effective for increasing the adhesion of the matrix to the fibers.
Examples of the binder are organic silicon polymers such as diphenylsiloxane~ dimethylsiloxane, polyborodiphenylsiloxane, polyborodimethylsiloxane, polycarbosilane, polydimethylsilazane, polytitano-carbosilane and polyzirconocarbosilane and organic silicon compounds such as diphenylsilanediol and hexa-methyldisilazene.
The aggregate of the carbonaceous material and the fibers may be molded, for example, by a method com-r ~ ~3 ~
prising carbon powder optionally containing ~he binder to the reinfocing fibers, and moldiny the m.ixture by using a rubber press, a mold or a hot press, or a method com-prising impregnating a so~lution of a ~hermose~ting or thermcplastic resin in a bundle of the fibers or a woven fabric of the fibers, drying and removing ~he solvent~
and molding the prepreg sheets by an ordinary method of molding an ordinary FRP, or a method comprising laminat-ing prepreg sheets on a mold, and molding them by a hot 1 n press~
The resulting molded article, if required~ isrendered infusible, and then in an inert atmosphere, heated at 80a to 3000 9C to carbonize the matrix com-ponentO
The resulting fiber~rein~orced material may directly be used in various applications. Alternatively, it may be further repeatedly subjected to a step of impregnating it with a melt or solution of a thermo-plastic or thermosetting resin and carbonizing the coated material to give a higher density and a higher strength.
In particular, where mechanical properties are required, the density of the material can be effectively increased by a vapor-phase method such as CVI.
In the fiber-reinforced carbon material ob-tained, the reinforcing fibers are the fibers of thisinvention having high strength and high modulus~ and have improved adhesion to the carbon matrix. Accordingly, the resulting fiber-reinforced carbon material has high strength, modulus and tenaciousness and also excellent practical mechanical properties such as abrasion resist-ance~
Accordingly, the resul~ing composite materials may advantageously be used in various kinds of brakes and heat-resistant structural materials.

r--- 4~1 --Fiber-reinforced composite materials including a sintered body matrix producecl from the polymer com-position of the invention~-These composite matelials include a composite material comprising the first fibers of the invention asthe reinforcing fibers and a carbonized product of the first polymer composition of the invention as the matrix;
a composite material comprising the first ibers of the invention as the reinforcing fibers; and a carbonized 1~ product of the second polymer composition of the invention as the matrix; a composite material comprising the second fibers of the invention as the reinforcing fibers and a carboni~ed product of the first polymer composition of the invention as the matrix; and a com-posite material comprising the second fibers of theinvention as the reinforcing fibers and a carbonized product of the second polymer composition of the invention as the matrix.
To describe these composite materials com-prehensively, the ~first and second" qualifying thefibers and the polymer compositivns will be omitted hereinafter~
A fiber-containing molded ar~icle is produced by, for example, a method comprising adding a powder of the polymer composition to a fabric of the fibers such as a plain weave fabric, a satin weave fabric, an imitation gauze fabric, a twill fabric, a helical woven fabric or a three-dimensionally woven fabric~ a method comprising impregnating the fabric with a solution or slurry of the polymer composition, remo~ing the solvent, drying the impregnated fabric, and heat-molding the prepreg sheet, or a method comprising melt-kneading the short fibers or chopped fibers with the polymer composition and molding the mixture by compression or injection molding. At this time~ the content of the fibers in the molded article is preferably 10 to 70 % by volume~ The polymer composition r~

- ~5 --of this invention as such may be used in this stepO
However~ since it is not necessary ~o flberize the polymer composi~ion further, thle ratio o~ silicon to carbon may be set within a slig;htly broader range than in the case o the composition of this invention.
The proportions of khe optically isotropic pitch used may be adjusted to llD to 4,900 parts by weight per 100 parts by weight of the organic silicon polymer~
The proportion of the mesophase pitch may be adjusted to 5 to 50,000 parts by weight per 100 parts by weight of the reacti.on product of the organic sil.icon polymer and the isotropic pitch.
In the production of the fiber-containing molded article, the polymer composition may be used as a mixture of it with a calcined inorganic powder obtained by pyrolyzing the polymer composition at 800 to l,OD0 C in an inert atmosphere.
This calcined powder preferably consists es-sentially of 0~01 to 69.9 ~ of Si, 2~.9 to 99.9 % of C
and 0.01 to 10 % of O if it does not contain a transition metal compound. If it contains a tansition metal, it preferably consists essentially of 0.005 to 30 ~ of the transition metal, 0.01 to 69.9 ~ of Si, 29.9 to 99~9 ~ of C and 0~01 to 10 % of O.
Then, as required, the product i5 subjected to a curing treatment.
The methods of curing in the production of the fibers o this invention may be directly used to perorm this treatment.
The molded article rendered infusible is pyrolyzed at a temperature of 800 to 3~000 C in vacuum or in an inert gas to give a composite material contain-ing a matrix composed of carbon, silicon and oxygen, which is carbonized and fiber-reinforced.
It is presumed that in the process of heating, carboniz~tion begins to be vigorous at about 700 C, and P

is nearly ~ompeleted at about 800 C. It is preferred therefore to perform pyrolyzing at temperatures of 800 QC
or above. To obtain temperaturles higher than 3 r C
requires expensive equipment, and pyrolyzing at high temperatures above 3,000 ~ is not practical from the viewpoint of cost.
The step of curing ma~y be omitted by greatly decreasing the temperature-elevation rate for carbo-nization in this step or by using a shape retaining jig for the molded article, or a shape retaining means such as a powder head. By performing the molding with a high temperature hot press, a high-density composite can be obtained in one step.
The fiber-reinforced carbonaceous composite material obtained by pyrolyæing and carbonization con-tains some open pores. If re~uired, it may be im-pregnated with a molten liquid, solution or slurry of the polymer composition and then pyrolyzed and carbonized after optionally it is cured. This gives a composite haviny a higher density and higher strength. The im-pregnation may be effected by any oE the molten liquid, solution and slurry of the polymer composition. To induce permeation into fine open pores, after the com-posite material is impregnated with the solution or slurry of the polymer compositionr it is placed under reduced pressure to facilitate permeation into the fine pores. Then, it is heated while evaporating the solvent, and subjected to a pressure of 10 to 500 kg~mm2. As a result, the molten liquid of the polymer composition can be filled in the pores.
The resulting impregnated material can be cured, pyrolyzed and carbonized in the same way as above~
By repeating this operation 2 to 10 times, a fiber-reinforced composite material having a high density and high strength can be obtained.
This fiber-reinforced carbonaceous composite - ~17 ~
material is characteY:ized by having high strength, high modulus of elasticity and excellent tenaciousness since, the reinforcing fibers have high streng-~h and modulus of elasticity, and improved adh2sion to the carbon matrix.
F~rthermore, it has excel~ient oxidation resist~
as~ce and abrasion resistance attributed to the efect of the siliicon carbide component contained in the fibers and the matri~O Accordingly, this composite material have excellent mechanical properties~ oxidation resist-ance and abrasion resistance~ and is useful as various ~ypes o~ brakes and thermally resistant structural materials~
Fiber-reinforced composite materials including a metal as a matrix:-The first and second fibers of this invention may he used directly as the reinforcing fibers. They may also be used as fibers to which at least one adhering material selected from the group consisting of fine particles, short fibers and whiskers of thermally resist-ant materials.
First, a method of adhering at least one ad-hering material selected from the group consisting of fine particles, short ~ibers and whiskers of thermally stable materials to the surface of the fibers of this invention provided as continuous filaments will be described.
Examples of the thermally stable materials are metals, ceramics and carbon.
Specific examples of the metals as the thermally stable materials are steel, stainless steelt molybdenum and tungsten. Specific examples of the ceramics include carbides such as SiC, TiC~ WC and B4C, nitrides such as Si3N~, BN and AlN, borides such as TiB2 and ZrB2 and oxides such as A12O3, B2O3, MgO, ZrO2 and SiO2. Other examples of the ceramics include poly-carbosilane compositions, polymetallocarbosilane com-- ~8 -positions, and cal~ination produc-ts of the first and ~econd polymer compositions of this invention.
The forrn of the adhering material differs depending upon the combination of it with the continuous inorganic filaments or the required properties. The short fibers or whiskers of the adhering material desir~
ably have an average particle diameter 1/3~000 to 1/5 of that of the continuous filaments and an aspect ratio of from 50 to 1,000. The fine particles desirably have an average diameter 1/5,000 ts 1/2 of that of the continuous fibers.
The amount of the adhering material to be applied to the continuous fibers differs depending upon the properties of both, and the use of the fiber-rein-forced composite produced~ In the case of using it forfiber-reinforced metals, the volume ratio of the adhering material based on the continuous filaments is preferably about Ool to 500 %.
The adhering materials may be used singly or in combination. For example, when the fibers of this inven-tion are to be used for reinforcing Al containing Co, Si, Mg and Zn, it is especially preferable to apply the fine particles to the neighborhood of the surface of the continuous fibers and apply the short fibers and/or the whiskers to the outside of the fine particles in order to prevent microsegregation of the added elements on the surface of the continuous filaments. In this case, the suitable ratio of the fine particles to the short fibers and/or the whiskers is from 0.1:5 - 40:1.
It is preferred to immerse the continuous filaments in a su~pension of the adhering material be-cause it is simple and has a wide range of application.
Figure 1 shows one example of the outline of an apparatus used in the production of the above fibers.
A bundle 4 of continuous filaments (a woven fabric from the contilluous filament bundle may be used ~C
- ~9 -instead of the continuous filament bundle~ wound on a bobbin 5 is unwound, conducted by movable rollers 6 and 7, and passed through a liquid 3 in which the adhering material is suspended. Then, it is pressed by press rollers 8 and 9 and wound up on a bobbin 10. In the resulting filament bundle or fabric, the adhering material adheres to the surface of every individual continuous filament~ There may be one treating vessel 1 containing a treating liquor 3. For various modiEied methods~ two or more tgeating vessels containing treating liquors of different compositions respectively may be used.
To promote the adhesion of the adhering material to the continuous filaments, ultrasonic vibra-tion 2 may be applied to the treating liquor 3. In thecase of applying two or more kinds of the adhering material to the continuous filaments~ the treating liquor may be a suspension of the fine particles and the short fibers and/or whiskers, or it is possible to use two treating vessels one containing a suspension of the fine particles as the treating liquor and the other containing a suspension of the short fibers and/or whiskers as the treating liquor. In the latter case, the sequence of immersing the continuous filament bundle or the woven fabric may start with the suspension of the fine par-ticles or the suspension of the short fibers and~or whiskers.
Since the fibers having the adhering material are composed of a continuous filament bundle in which the adhering material adheres to the surface of every in-dividual filament of the invention having high strength and high modulus of elasticity, these continuous fila-ments can be uniformly dispersed in the composite material, and the volume ratio of the fibers can be controlled to a very broad range. Furthermore, the contact among the continuous filaments decreases, and the r.~ r~3 resulting composite material has a uniform composition~
This brings about the advantage of improving the mechanical properties such as strength of the composite material~
The reinforcing fibers may De applied to the matrix by, for example, arranging the fibers themselves in the monoaxial or multiaxial direction, or used in the fvrm of various woven fabrics such as a plain weave fabric, a satin weave fabric, an imitation gauze fabric a twill fabric, a helical woven fabric or a three-dimensionally woven fabric, or in the form of chopped fiber, to give the composite material of this invention.
Metals that can be used in this invention may be, for example, aluminum, aluminum alloys, magnesium, magnesium alloys, titaniuum, and titanium alloys.
The mixinq proportion of the reinforcing fibers in the matrix is preferably 10 to 70 % by weight.
The composite material can be produced by the following methods of producing ordinary fiber-reinforced metal composite materials. There are (1) a diffusion bonding method, (23 a melting permeation method, ~3) a flame spraying method, (4~ an electrolytic deposition method, (5) an extrusion and hot roll method, (6) a chemical vapor-phase deposition method, and (7) a sintering method.
tl) According to the diffusion bonding method, a composite material of reinforcing fibers and a matrix metal can be produced by aligning the reinforcing fibers and wires of the matrix metal alternately in one direc-tion, covering the upper and lower suraces of the ar-rangement with a thin coating of the matrix metal, or covering only the lower surface of it with the above thin coating and the upper surface of it with a powder of a mixture of the matrix metal and an organic binder to form a composite layer, laminating a plurality of such com-posite layers, and consolidating the laminate under heat and pressure.

The organic binder desirably volatili~es and dissipate6 before it is heated to a temperature at which i~ forms a carbide with the matrix metalO For example, CMC, paraffins, resins and mineral oils may be used.
Alternatively, the colmposit2 material may also be produced by bonding and coating a mixture of the matrix metal powder and the organic binder to the ~ur-faces of the reinforcing fibers, aligning and laminating a plurality of layers of such fibers, and consolidating the laminate under heat and pressure.
~ 2) According to the melting permeation method, the composite material can be produced by filling the interstices of tbe aligned reinforcing fibers with molten aluminum, aluminum alloy, magnesium, magnesium alloy, titanium or titanium alloy. Since the wettability of the metal-coated fibers with the matrix metal is good, the interstices of the aligned fibers can be filled uniformly with the matrix metal.
(3) According to the flame spraying method, a tape-like composite material can be produced by coating the matrix metal on the surface of aligned reinforcing fibers by plasma flame spray or gas flame spray~ It may be used directly, or a plurality of the tape-like com-posite materials are laminated and subjected to the diffusion bonding method ~1) to produce a composite material.
~ 4) According to the electrolytic deposition method, a composite material can be produced by electro-lytically depositing the matrix metal on the surface of the reinforcing fibers, laminating a plurality of the composite materials, aligning them, and subjecting tbe lamination to the diffusion bonding method ~1).
~ 5) According to the extrusion and hot roll method, a composite material can be produced by aligning the reinforcing fibers in one direction, sandwiching the aligned reinforcing fibers between foils of the matrix t~

metal 7 optionally passing the sandwich structure between heated rolls to bond the Eibers and the matrix metal.
(6~ According to the chemical vapor deposition method~ a composite material can be produced by placing the fibers in a heating furnace, introducing a gaseous mixture of~ for example~ aluminum chloride and hydrogen to thermally decompose the gas to deposit aluminum metal on the surface of the fibers, and laminating the metal-deposited fibers, and subjecting the laminate to the diffusion bonding method (1).
~ 7~ According to the sintering method~ a composite material can be produced by filling a powder of the matrix metal in the interstices of aligned fibers~
and sintering the resulting product under pressure or without pressure.
The tensile strength (~) of the composite material produced from the inorganic fibers and the metal matrix is represented by the above equation (see the above description on the composite material including a plastic matrix).
As shown by the above equation, the strength of the composite material becomes higher as the volume proportion of the reinforcing fibers in the composite material becomes larger. Hence, to produce a composite material having high strength, it is necessary to increase the volume proportion of the reinforcing fibers~
However, if the volume proportion of the reinforcing fibers exceeds 70 %, the amount of the metal matrix is small so that the intersices of the reinforcing fibers cannot be fully filled with the metal matrix. Hence, the composite material produced cannot exhibit the strength shown by the above equation. If the volume proportion of the reinforcing fibers in the composite material is decreased, the strength of the composite material de-creases as shown by the above equation. To obtaina composite material having practical utility, it is mecessary to combine at least 10 % of the reinforcing fibers~ Accordillgly, if the voLume proportion of the reinforcing fibers is limited to 10 to 70 ~ by volume in the production o the fiber-reillforced metal composite material 9 the best result can be obtained~
In the production oE the compositc material, it is necessary to heat the metal to a temperature near the melting point or a higher temperature as stated above, and combine it with the reinforcing fibers. Thus9 the reduction of fiber strength by the reacion of the rein-forcing fibers with the molt~n metal gives rise to a problem. But when the fibers of this invention are immersed in the molten metal, the abrupt degradation seen in ordinary carbon fibers is not observed, and therefore, a composite material having excellent mechanical strength can be obtained.
The methods of measuring the various mechanical properties used in this invention will be described.
(a) Initial rate of degradation induced by 2n reaction tl~ In the case of metals and alloys having a melting point of not more than 1200 C
The fibers are immersed for 1, 5, 10, and 30 minutes respectively in a molten metal heated to a tem-perature 50 C higher than the melting point of the metal. Then, the fibers are extracted, and their tensile strength is measured. From the results obtained, a reaction degradation curve showing the relation between the immersion time and the tensile strength of the fibers is determined. From a tangent at an immersion time of 0 minute, the initial rate of degradation induced by reac-tion tkg~mm2-sec 1) is determined.
(2) In the case of metals and alloys having a melting point higher than 1200 ~C
The fibers are laminated to a metal foil~ The laminate is placed under vacuum, heated to a ternperature -- 5~ --of (the melting point of the metal foil) x (0.6-0.7), and maintained under a pressure of 5 kg/mm2 for 5, 10, 20 and 30 minutes~ respectivelyD Then, the fibers are extracted, and their tensile streng~h is measured~
From the results, the ini~ial rate of degrada-tion induced b~ reaction is detlermined by the same pro-cedure as in (1).
(b) Ratio of fiber strength reduction The fiber strength at an immersion time and a maintenance time sf 30 minutes in (a) above is deter-mined. The ratio of fiber strength reduction is cal-culated by dividing (the initial strength - the fiber strength determined abovej by the initial strength.
The initial rate of reduction by reaction shows the degree of the reaction between the fibers and the matrix in the production of a fiber-reinforced metal within a short time~ The smaller this value~ the better the affinity between the fibers and the matrix and the larger the fiber reinforcing effect.
(c) Interlayer shear strength test The same as the method described above with respect to a composite material comprising plastics as a matrixO
~d) Fatigue test A round rod (10 mm in diameter x 100 mm in length) is produced from a composite material in which the inorganic fibers are aligned monoaxially. The axial direction of the composite material is the longitudinal direction of the rod~ The rod is worked into a tes~
specimen for a rotational bending fatigue test. The specimen is subjected to a rotational bending fatigue test with a capacity of 1.5 kgm, and its fatigue strength after 107 times is measured and defined as the fatigue.
The ratio of the fatigue strength and the tensile strength is an index showing the strength of bonding between the matrix and the fibers.

Since the degradation of the fiber strength due to the reaction with the molten metal is little in the fibers of this invention, the fiber-reinforced ~etal composite materials including the fibers of this inventioll have excellent tensile strength and other mechanical properties, high modulus of elasticity and excellent thermal resistance and abrasion resistance.
Accordingly, they are useful as various material in various technological fields such as synthetic fibers, synthetic chemistry, machine industry, construction machinery, marine and space exploitation~ automobiles and f oods~
According to this invention, a carbonized sintered body can be produced from a polymer composition by the following procedure.
Examples of the polymer composition that can be used at this time are the first and second polymer com-positions of the inventi~n~ and polymer compositions having a slightly broader chemical composition than the polymer compositions of this invention, which are de-scribed with reEerence to the description of fiber-reinforced composite materials comprising a carbonized product of the polymer composition of the invention as a matrix.
The polymer composition or a mixture oE the polymer composition and its calcination product is first finely pulverized, and can be molded by using a method of molding an ordinary carbonaceous material. The calcina-tion may be carried out at a temperature of 800 to 30 1300 C.
The molding method can be selected from the molding methods for ordinary carbonaceous material by considering shape, size, use of the molded product and the productivity of molding. For example, for production oE articles of the ~ame shape with good productivity, a dry mold press method is suitable. To obtain molded - 5~ -articles of a slightly complex shape7 an lsostatic mold-ing method ~rubber press molding method) is suitableO
For molding a molten mass of the above polymer, a hot press molding method, an injection molding method and an extrusion molding method are suitable.
In the case of molding the mixture of the polymer composition and its calcination product, the proportions of th2 polYmer composition and its calcina-tion product may be properly determined by considering the shape, use and cost of the molded article to be obtained.
The molded article is then subiected to an curing treatment.
A typical method of curing is to heat the molded article in an oxidizing atmosphere. The curing temperature is preferably 50 to 400 ~C~ If the curing temperature is excessively low, bridging of the polymer does not take place. If this temperature is excessively high r the polymer burns.
The purpose of curing is to render the polymer constituting the molded article in the three-dimensional infusible insoluble bridged state and to have the molded article retain its shape without melting during carbo-nization in the next step. The gas constituting the ~S oxidizing atmosphere during curing may be, for exampe, air, ozone, oxygen, chlorine gas, bromine gas, ammonia gas, or mixtures of these gases.
An alternative method of curing which may also be used comprises applying gamma-ray irradiation or electron beam irradiation to the molded article in an oxidizing or non-oxidizing atmosphere while as required heating it at low temperatures.
The purpose of gamma ray or electron beam irradiation is to prevent the matrix from melting and losing the shape of the molded article by further poly~
merizing the polymer constituting the molded article.

The suitable irradiation dose of yamma rays or electron beams is 106 to 101 rads.
The irradiation may be carried out in vacuum, in an inert gas atmosphere or in an atmosphere of an oxidizing gas such as air, oæone~ o~ygen, chlorine gas, bromine gas, ammonia gas or mixtures of these.
curing by irradiation may also be carried out at room temperature. If required, by performing it while heating at a temperature of 50 to 200 C~ the curing may be achieved in a shorter period of time~
The molded article rendered infusible is then pyrolyzed and carbonized at a temperature of 800 to 3000 C in vacuum or in an inert gasO
It is presumed that in the heating process, carbonization begins to become vigorous at about 700 C, and is nearly completed at about 800 C. Hence, the pyrolyzing i5 preferably carried out at a temperature of at least 800 C. To obtain temperatures higher than 3000 3C, expensive equipment is required. Accordingly, pyrolyzing at high temperatures higher than 3000 C is not practical in view of cost.
The curing step may be omitted by making the temperature elevation rate for carbonization in this step very slow, or by using a jig for retaining the shape of the molded ~rticle or a shape retaining means such as a powder head. Alternatively, by using a high temperature hot press method in this molding step, the next step may be omitted.
~s required, the resulting carbonaceous material may be impregnated with a melt, solution or slurry of the polymer solution, and pyrolyzed for carbonization~ This further increases the density and strength of the carbonaceous material.
For impregnation, any of the melt, solution and slurry of the polymer composition may be used. To facili-tate permeation into fine open pores, the carbonaceous s~ g~

material after impregnation with the solu~ion or slurry of the polymer composition is placed under reduced pres~
sure to facilitate permeation into the fine pores~ heated while evaporating the solvent, and pressed under 10 to 5~0 kg/cm2 thereby to Eill the melt of the polymer composition into the pores.
The carbonaceous material impregnated with the polymer composition may be cured, pyrolyzed and carboni~ed in the same way as in the previous step~ By repeating this operation 2 to 10 times, a carbonaceous material having high density and high s,rength can be obtained.
The state of existence of Si, C and O in the silicon-containing component corresponding to the con-stituent (iii) of the first fibers in the resultingearbonaceous material can be controlled by the carbo~
nization temperature in the above-mentioned step.
When it is desired to obtain an amorphous material consisting substantially of Si, C and O, it is proper to adjust the carbonization temperature to 800 to 1000 C. If it is desired to obtain a material con-sisting substantially of beta-SiC and amorphous SiOx (O~x<2), temperatures of at least 1700 C are suitable.
When a mixture of the aggregates is desired, temperatures intermediate between the above temperatures may be properly selected.
The amount of oxygen in the carbonaceous material of this invention may be controlled, for example, by the curing conditions in the above 3~ curing step.
The state of existence of Si, M, C and O in the silicon-containing component corresponding to component ~iii) of the second fibers may be controlled likewise~
The resulting carbonaceous material contains a silicon carbicle component very uniformly dispersed and integrated in carbon. The presence of this component ~3~

promotes microcrystallization of oarbon at low tem-peratures, inhibition of consumption of carbon by oxidation, and the increase of hardness.
The carbonaceous material, therefore, has excellent mechanical properties, oxidation resistance and abrasion resistance and can be advantageously used as vario~s types o~ brakes and thermally stable structural materials.
Brief Description ~f the Drawing Figure 1 is an outline view of an apparatus used for applying thermally stable fine particles to the surface of the fibers of this invention.
In the following examples, the weight average molecular weight and the softening point were measured by the following methods.
The weight average molecular weight (Mw) is a value dertermined by the following procedure.
If the pitch is soluble in GPC measuring solvent ~chloroform, T~F or o-dichlorobenzene), it is dissolved in that solvent, and its molecular weight is measured by using an ordinary separation column.
The concentration of the sample is not par~
ticularly limited because integration may be carried out freely. The suitable concentration is 0.01 to 1 ~ by weight.
On the other hand, when the pitch contains components insoluble in the above organic solvent, it is subjected to a hydrogenation treatment under mild conditions to hydrogenate part of the aromatic rings without cleaving the carbon-carbon bonds to render it solvent-soluble. Then, its GPC measurement is conducted.
The hydrogenation method wih lithium and ethylenediamine described by J. D. Brooks and H.
Silverman ~Fuel, 41, 1962, p. 67-69) is preferred because the hydrcgenation can be performed under mild conditions below 100 C.

3~

The results of the GPIC measurement usua-].ly have a broad distribution, and Mw is determined by ap proximation to one peak~
The softening point is measured by using a commercial thermal analysis system,. :Eor e~ample, Metler FP~oO Ther~osystem~ Specifically, a sample is filled in a sample cylirld2r having an open pore portion at the bottom, and heated at a rate of ~ C/min., and the Elowing of the sample from the pore portion by softenlng is optically detected, and the softening point is deter-mined~

EX~MPLES
The following examples illustra-~e the present inven-tion.
ReEerence Example 1 In a 5-liter three-necked flask were placed 2.5 li-ters of anhydrous ~ylene and 40() g or sodium. The -Elask inside was heated to the boiling point of xylene in a nitrogen gas current, and 1 liter oE dime-thyldichloro-silane was dropped into the flask in 1 hour After the completion of -the dropping, the flask contents was sub-jected to reEluxing with heating for 10 hours to form a precipitate. The precipita-te was collected by filtration and washed with methanol and water in this order to obtain 420 g of a polydimethylsilane as a white powderO
400 g of -this polydimethylsilane was fed into a 3-liter three-necked flask provided with a gas-blowing tube, a stirrer, a cooler and a distillate tube and subjected to a heat treatment at 420 ~C with s-tirring in a nitrogen current of 50 ml/min. to obtain 350 g of a colorless transparent slightly viscous liquid.
The liquid had a number-average molecular weight of 470 as measured by an osmo-tic pressure method.
The substance, as measured for infrared absorp-tion spectrum, showed absorptions of Si-CH3 at 650 -900 cm 1 and 1250 cm 1, Si-H at 2100 cm ~ Si-CH2--Si at 1020 cm~l and 1355 cm~l and C-H at 2900 cm 1 and 2950 cm 1 The substance, as measured for Ear infrared absorption spectrum, showed an absorption of Si-Si at 380 cm-l~
It was confirmed from the results of NMR analy-sis and infrared absorption analysis that the aboveorganosilicon polymer was a polymer wherein the ratio of the total number of tSi-CH2) units to the total number of (Si-Si) units is about 1:3.
300 g of the above organosilicon polymer was treated with e-thanol to remove a low-molecular portion to obtain 40 g of a polymer having a number-average mole-culer weight of 1200.
This substance was measured Eor infrared absorp-tion spectrum, which gave the same absorption peaks as above.
It was confirmed from the results of NMR analy-sis and inErared absorption analysis that the organo-silicon pol~mer was a polymer wherein -the ratio oE the to-tal number of (Si-CH2) units to the total number of (Si-Si) units was about 7:1.
ReEerence Example 2 High-boiling pe-troleum fractions (gas oil and heavier Eractions) were subjected to Eluid catalytic cracking and rectification at 500 C in the presence o-f a silica-alumina cracking catalyst, and then a residue was obtained from the rectifier bottom. Hereinaf-ter, this residue is referred to as FCC slurry oil.
The FCC slurry oil had a C/H atomic ratio of 0.75 by elemental analysis and an aromatic carbon ratio of 0.55 by NMR analysis.
Example 1 (First step) 100 g of the FCC slurry oil obtained in Refer-ence Example 2 was heated for 2 hours at 420 C in a nitrogen gas current of 1 liter/min to remo~e the 420 C
fraction. The residue was filtered at 150 C to remove the portion which was not in a molten s-tate at 150 C, and thereby to obtain 57 g of a lighter reforming pitch.
The reforming pitch had a xylene insoluble content of 60%.
57 g of the pitch was mixed with 25 g of the organosilicon polymer obtained in Reference Example 1 and 20 ml of xylene. The mixture was heated with stirring and, after distilling ofE xylene, was subjected to a reac-tion for 6 hours at 400 ~C to obtain 43 g of a reac-tion product.
Infrared absorption spectrum analysis indicated that in the reaction product there occurred the decrease r -of the Si-H bond (IR: 2100 cm 1) present in or~anosilicon polymer and the new Eormation of Si-C (this C is a carbon of benzene ring) bond (IR: 1135 cm~ Therefore, i-t became clear that the reaction product contained a 5 structure in which part of the silicon atoms of organo-silicon polymer bonded direc-tly with a polycyclic aroma-tic ring.
The reac-tion product con-tained no xylene in~
soluble and had a weight-average molecular weight of 1450 and a melting point of 265 C O
(Second step) 400 g of the FCC slurry oil obtained in Refer-ence Example 2 was heated for 1 hour at 450 ~C in a nitrogen gas current of 1 liter/min to remove the 450 C
fraction. The residue was filtered at 200 C to remove the portion which was not in a molten state at 200 C, and thereby to obtain 180 g of a reforming pitch.
180 g of the reforming pitch was subjected to a condensation reaction for 8 hours at 400 C in a nitrogen 20 current while removing the light fractions formed by the reaction, to obtain 80.3 g of a heat-treated pitch. This heat-treated pitch had a melting point of 310 C, a xylene insoluble content of 97% and a quinoline insoluble conten-t of 20~. The pitch was a meso phase pitch having an optical anisotropy of 95 % when the polished surface was observed by a polarizing microscope.
(Therd step) 40 g oE the reaction product obtained in the first step and 80 g of the mesophase pitch obtained in the second step were melt mixed for 1 hours at 350 C in a nitrogen atomosphere to obtain a uniform silicon-containing reaction product.
This silicon-containing reaction product had an optical anisotropy of 51 %, a xylene insoluble content of 68 % and a melting point of 281 C. The reaction product, when subjected to a hydrogenation reaction under mild - 6~ -conditions and suhsequently to the measuremen-t of weight-average mo.Lecular weight by gel permeation chromatography tGPC), had a ~w of 1250.
The above silicon-containing reac-t.ion product was heated a-t 1000 ~C in air; -the resulting ash was subjected to alkali ~usion and then to a hydrochloric acid -treatment, and dissolved in wa-ter; the aqueous solution was measured for silicon concen-tration using a high frequency plasma ernission spectrochemical analysis apparatus (ICP), which indicated that the silicon content in the si]icon-containing reac-tion product was 5~2 ~.
Examples 2-8 Various silicon-containing reaction products were obtained by varying the feeding ratio of -the organo-silicon polymer and the reforming pitch and their copoly-merization conditions in the first step of Example 1, -the heat treatment conditions in the second step of Example 1, and the feeding ratio and the melt mixing (melt con~
densation) conditions in -the third step of Example 1.
The results are shown in Table 1 together with -the re-sults of Example 1. In all the Examples, the obtained silicon-containing reaction product had a silicon content of 0.4-24.8 ~ and an optical anisotropy.

3~3 Comparative Example 1 (First step) 200 g of the ~'CC slurry oil obtalned in Refer-ence Example 2 was heated for 2 hours at 420 C in a nitrogen gas curren-t of 1 liter/min to remove the 420 C
fraction and thereby to obtain 114 g of a reforming pitch. The pitch was dissolved in 500 ml of xylene of 130 C to remove 69 g of the xylene insoluble portion.
The resulting xylene soluble pitch portion (45 g) was mixed with 45 g of the organosilicon polymer obtained in Reference ~xxample 1, and the mixture was subjected to a copolymeri~ation reaction for 6 hours at 400 C to obtain 32 g of a reaction product.
(Second step) 200 g of the xylene soluble pitch component was subjected to a heat treatment for 6 hours at 400 C in an inert atmosphere to obtain 41 g of a heat-teated pitch.
(Third step) 30 g of the reaction product obtained in -the first step and 60 g of the heat-treated pitch obtained in the second step were mixed with heating for 2.5 hours at The product obtained above had a weight-average molecular weight (~w) of 1750 and a silicon content of 10.5 %, bu-t had a low me]ting point of 198 C and a low xylene insoluble content of 11 % and was optically iso-tropic.
Comparative Example 2 100 g of the reforming pitch obtained in the first step of Example 1 was mixed with 50 g of the organo-silicon polymer obtained in Reference Example 1, and the mixture was subjected to a reaction for 6 hours at 400 C
to obtain 79 g of a reaction product.
The reaction product had a melting point of 252 C and a silicon content of 15 ~ and contained no xylene insoluble and no mesophase portion.

Example 9 Each of the silicaon-containing reaction pro-ducts ob-tained in Examples 1 and 2 was used as a spinning dope and subjected to melt spinning using a spinning nozzle of 0.3 mm in diameterA The resu~ting precursor fiber was cured at 300 C in an air current and then subjected to pyrolyzing at 1300 ~C in an argon current to obtain two carbonaceous inorganic fibers. The carbonace-ous inorganic fiber producted from the Example 1 dope had a diameter of 14 ~, a tensile strength of 190 kg/mm2 and a -tensile modulus of elasticity of 18 t/mm2, and the carbonaceous inorganic fiber produced from the Example 2 dope had a diameter of 17 ~, a tensile strength of 161 kg/mm2 and a tensile modulus of elasticity of 16 t/mm2.
Observation by a scanning type electron micro-scope indicated that the both fibers had a sec-tional structure similar to the radial structure preferably used in pitch fibers and, in the two fibers, the mesophase component which had been present in the respective dopes was orientated to the fiber axis airection by the spin-ning, curing and pyrolyzing procedures.
Comparative Example 3 Each of the reaction products obtained in Comparative Examples 1 and 2 was subjected to spinning, curing and pyrolyzing under the same conditions as in Example 9 to obtain two pyrolyzed fibers. The Eiber obtained from the Comparative Example 1 dope had a dia-meter of 17 ~, a tensile strength of 105 kg/mm2 and a tensile modulus of elasticity of 7.1 t/mm2~ and the fiber obtained from the Comparative Example 2 dope had a dia-meter of 16 ~, a tensile strength of 75 ~g/mm2 and a tensile modulus of elasticity of 5.0 t/mm2.
The sections of these fibers contained no structure showing orientation.
Example 10 (First step) 200 g of the FCC slurry oil obtained in ~efer-ence Example 2 was heated for 0.5 hours at 450 C in a nitrogen gas current of 2 liters/min to remove the 450 C
fraction. The residue was fi]~ered at 200 C to remove -the portion which was not in a molten state at 200 C and thereby to obtain 57 g of a reforming pi-tch.
This reforming pitch had a ~ylene insoluble content of 25 %.
57 g of -the pitch was mixed with 25 g of -the organosilicon polymer obtained in Rference Example 1 and 20 ml of xylene. ~he mixture was heated with stirring to remove xylene and then subjected to a reaction Eor 6 hours a-t 400 C to obtain 51 g of a reaction productO
Infrared absorption spectrum analysis indicated that in the reaction product there occurred the decrease of the Si-H bond ~IR: 2100 cm~l) present in organosili,con polymer and the new formation of Si-C (this C is a carbon of benzene ring) bond (IR: 1135 cm-l). Therefore, it became clear that the reaction produc-t contained a struc-ture in which part of the silicon atoms of organosilicon polymer bonded directly with a polycyclic aromatic ring.
The reaction product contained no xylene in-soluble and had a weight-average molecular weight of 1400, a melting point of 265 C and a softening point of 310 C.
(Second step) 180 g of the reforming pitch was subjected to a condensation reaction for 8 hours at 400 C in a nitrogen current while removing the light fractions Eormed by the reaction, to obtain 97.2 g of a heat-treated pitch. The heat-treated pitch had a melting point of 263 C, a softening point of 308 C, a xylene insoluble content of 77 % and a quinoline insoluble content of 31 ~. Obser-vation by a polarizing microscope indicated that the pitch was a mesophase pitch having an optical anisotropy Of 75 ~, (Third step) 70 _ ~ .4 g of the reaction product obtained in the first step and 90 g of the mesophase pitch obtained in the second step were melt mixed Eor 1 hour at 380 C in a nitrogen atomosphere to obtain a uniform silicon-contan-ing reaction product.
This silicon-containing reaction product had an optical anisotropy of 61 %, a xylene insoluble content of 70 ~, a melting point of 267 ~C and a softening point of 315 C.
The reaction product was subjected to hydro-genation under mild conditions and then to gel permeation chromatography (GPC) to measure the weight-average mole-cular weight (~w) of the reaction product. The ~w was 900 .
The silicon-containing reaction product was heated to 1000 ~C in air; the resulting ash was subjected to slkali fusion and then to a hydrochloric acid treat-ment, and dissolved in water; the aqueous solution was measured for silicon concentration using a high frequency plasma emission spectrochemical analysis apparatus (ICP), which indicated that the silicon content in the silicon containing reaction product was 0.91 ~. Examples 11-19 Various silicon-containing reaction products were obtained by varying the feeding ratio of the organo-silicon polymer and the lighter reforming pitch and theircopolymerization conditions in the first step of Example 10, the heat treatment conditions in the second step of Example 10, and the feeding ratio and the melt mixing (melt condensation) conditions in the third step of Example 10. The results are shown in Table 2 together with the results of Example 10. All of the silicon-containing reaction products obtained in Examples 11-19 had an optical anisotropy.

~¢3~3~

Example 20 The silicon-containing reaction products ob-tained in Examples 10, 11 and 19 were used as a spining dope and subjected to melt spinning using a nozzle of 0.15 mm in diame-ter. Each oE the resul-ting precursor fibers was cured at 300 C in an air corren-t and then pyrolyzed at 1300 C in an argon current to obtain three carbonaceous inorganic Eibers. ~`he fiber obtained from the Example 10 dope had a diameter of 8 ~, a tensile strength of 320 kg/mm2 and a -tensile modulus of elasti-city of 26 t/mm2; the fiber obtained from the Example 11 dope had a diameter of 9 ~, a tensile strength of 260 kg/mm2 and a tensile modulus of elastici-ty of 24 t/mm2;
and the fiber obtained from -the Example 19 dope had a 1~ diameter of 3 ~, a tensile strength of 300 kg/mm2 and a tensile modulus of elasticity of 22 t/mm2.
Observation by a scanning type electron micro-scope indicated that all the fibers had a sectional struture similar to the radial structure preferably used in pitch fibers and, in these fibers, the mesophase componnt which had been present in the respective dopes was orientated to the fiber axis direction by the spin-ning, curing and pyrolyzing procedures.
Example 21 (Firs-t step) 100 g of the FCC slurry oil obtained in Refer-ence Example 2 was heated for 2 hours at 420 C in a nitrogen gas current of 1 liter/min to remove the 420 C
fraction. The residue was filtered at 150 C to remove the portion which was not in a moleten state at 150 C
and thereby to obtain 57 g of a reforming pitch.
The reforming pitch had a xylene insoluble content of 60 ~.
57 g of the reforming pitch was mixed with 25 g of the organosilicon polymer obtained in Reference Example 1 and 20 ml of xylene. The mixture was heated with s-tirring and, a~ter removing xylene, was subjected to a reac-tion for 4 hours at 400 C to obtain 53 g of a reaction procluct. InErared absorption spec-trum analysis indicated tha-t in the reac-tion produc-t there occurred the decrease of the Si-H bond (IR: 2100 cm-l) present in organosilicon polymer and -the new formation of Si-C (this C is a carbon of benzene ring)bond (IR: 1135 cm-1).
Therefore, it became clear -that the reaction product contained a structure in which part of the silican atoms Of organosilicon polymer bonded directly with a po]y-cyclic aroma-tic ring.
The xeaction product contained no xylene in-soluble and had a weight-average molecular weight oE 1150 and a melting point of 245 C.
(Second step) 400 g of the FCC slurry oil ob-talned in Refer-ence Example 2 was heated to 420 C in a nitrogen gas current to remove the 420 C fraction. The residue was filtered at 150 C to remove the portion which was not in a molten state at 150 C, and then subjected to a conden-sation reaction for 9 hours at 400 C to ob-tain a heat-treated pitch. The pitch had a melting point of 265 C, a softening point of 305 C and a quinoline insoluble content of 25 ~. Observation of the polished surface of the pitch by a polarizing microscope indicated that the pitch was a mesophase pitch showing anisotropy.
This mesophase pitch was hydrogeneted at a hydrogen pressure of 100 kg/cm2 using a michel-cobalt solid catalyst (carrier: zeolite), for l hour at 360 C.
The hydrogenation product contained no quinoline in-soluble and, when the polished surface was observed by a polarizing microscope, was an optically isotropic pitch.
This pitch was kept for 30 minuites at 400 C in a nitro-gen current to effect heat stabilization and thereby to obtain a heated-treated pitch. The resulting pitch contained no quinoline insoluble, had a mel-ting point of 3~3 230 ~C and a so:Eteni.ng poing of 238 C, and was an iso-tropic pitch. This heat-trea-~ed pitch was mede into a fiber using a capi.llary of 0.5 mm in diameter; the fiber was cured at 300 C in air and pyrolyzed at 1000 C in a nitrogen current, and -the section of the resulting fiber was observedl which indicated that the fiber had orien-tation in the ~iber axis direction. Therefore~ the hea-t-trea-ted p.itch was found to be poten-tially aniso-tropic.
(Third step) 40 g oE the reaction product obtained in the first step and 80 g of the heat-treated pitch obtained in the second step were melt mixed for 1 hour a-t 350 C in a nitrogen current to obtain a uniform si.licon-containing reaction product.
This silicon-containing reaction product con--tained no quinoline insoluble and had a xylene insoluble content of 32 %, an optical isotropy, a melting point of 241 C and a softening point of 262 C. The reaction produc-t had a weight-averagge molecular weight (~w) of 980 as measured by gel permeation chromatography (GPC).
The silicon-containing reaction product was heated to 1000 C in air; the resulting ash was subjected to alkali fusion and then to a hydrochloric acid treat-ment, and dissolved in water; the resulting aqueoussolution was measured for silicon concentration by a high :Erequency plasma emission spectrochemical analyzer (ICP).
It indicated that the silicon content in the silicon-containing reaction product was 5.4 ~.
Example 22 (First step3 A reaction poroduct was obtained in the same manner as in the Eirst step of Example 21 except that the ratio of the reforming pitch and the organosilicon poly-mer was changed to 60 parts : 40 parts and the copolymeri-zation temperature and time were chanyed to 420 C and 2 hoursl respectively. The reaction prod~lct had a melting point of 238 C and a weight--average molecular weight (Mw~
of 1400 and contained no quinoline insoluble.
~Second step) The same procedure as in the second step of Example 21 was repeated except that the conditions for obtaining a rnesophase were 420 C and 4 hours and the hydrogenation was effected ror 2 hours a-t 95 C using metallic lithium and ethylenediamine, to obtain a heat-treated pitch. This heat-treated pitch had a melting point of 225 C and a softening point of 231 C and was confirmed by the same method as in Example 21 -to be potentially anisotropic.
(Third step) The same procedure as in the third step of Example 21 was repeated except that -the feeding ratio of the reaction product obtained in the above first step and the heat-treated pitch obtained in the above second step was 1:6 by weight and the mel;- mixing temperature wa 380 CF to obtain a silicon-containing reaction product.
This reaction product had a weight-avedrage molecular weight (Mw) of 800, a silicon content of 3.2 %, a melting point of 232 C and a softening point of 245 C.
Comparative Example 4 (First step) This was effected in the same manner as in Comparative Example 1.
(Second step) 200 g of the xylene-soluble pitch component obtained in the first step was heat-treated for 2 hours at 400 C in a nitrogen atomosphere to obtain 65 g of a pitch which contained no quinoline insoluble and which was optically isotropic. This pitch caused no orienta tion when subjected to shear by the method of Example 21 and accordingly contained no potantially anisotropic component.
(Third step) 3~ ~

'.0 g of the reaction product obtained in the firs-t step and ~0 g of -the heat-treated pitch obtained in the second step were mixed Eor 1 hour at 3A0 C~ The resulting product had a weight-average molecular weigh-t (Mw) of 1450 and a silicon--colltent of 9.8 % but a low melting point of 185 CO
Example 23 The silicon-containing reaction products ob-tained in Examples 21 and 22 were used as a spinning dope and subjected to melt spinning using a nozzle of 0.3 mm in diameter. The resulting precursor fibers were cured at 300 C in an air current and pyrolyzed at 130Q C in an argon current to obtain carbonized inorganic fibers.
The fiber obtained from the Example 21 dope had a dia-meter of 10 ~, a tensile strength of 260 kg/mm2 and atensile modulus of elasticity of 20 t/mm2. The fiber obtained from the Example 22 dope had a diameter of 9 u, a tensile strength of 290 kg/mm2 and a tensile modulus of elasticity of 24 t/mm~.
Observation by a scanning type electron micro-scope indicated that the both fibers had a sectional structure similar to the radial structure preEerably used in pitch fibers and, in the two fibers, the mesophase component which had been present in the respective dopes was oriented to the fiber axis direction by the spinning, curing and pyrolyzing procedures.
Comparative Example 5 The reaction product obtained in Comparative Example 4 was subjected to spinning, curing and pyrolyz-ing under -the same conditions as in Example 23 to obtain a fiber. The fiber had a diameter of 17 ~, a tensile strength of 95 kg/mm2 and a tensile modulus of elasticity of 6.0 t/mm2. The section of the fiber contained no portion of orientation struc-ture.
Example 24 (First step) This was effected in the same manner as in the 3s ~

first step of Example lr (Second step) 400 g of the FCC slurry oil obtained in Refer-ence Example 2 and 300 g of .l,2,3,4-tetrahydroquinoline were subjected to a hydrogenat;on treatmen-t for lQ
minutes at 450 C in an autoc]ave. Then, the te-txahydro-quinoline was removed by distillation to obtain a hydro-genated pitch.
The pitch was fed into a metallic container.
The container was immersed in a -tin bath under a reduced pressure of 10 mmHg to trea-t the pitch for 10 minu-tes at 450 C to obtain 62 g of a pitch.
The pitch had a melting point of 230 Ct a softening point of 238 C and a quinoline insoluble content of 2 %.
(Third step) 40 g of the reaction product obtained in the first step and 80 g of the pitch ootained in the second step were melt mixed for 1 hour at 350 C in a nitogen atomosphere to obtain a uniform silicon-containing reaction product.
This silicon-containing reaction product had an optical isotropy, a xylene insoluble content of 45 % and a melting point of 251 C. The reaction product, when hydrogenated under mil.d conditions and subjected to gel permeation chromatography to measure a weight-average molecular weight tMw), had a Mw of 1080.
The silicon-containing reaction product was heated to 1000 C in air; the resulting ash was subjected to alkali fusion and then to a hydrochloric acid treat-ment, and dissolved in wa-ter; the resulting aqueous solution was measured for silicon concentration by a high frequency plasma emission spec-trochemical analyzer (ICP).
I-t indicated that the silicon content in the silicon-containing reaction product was 5.8 % rExample 25 (First step) - The same procedure as in Example 24 was repeat-ed except that the ra-tio of the reforming pi-tch and the organosilicon polymer was changed to 60 parts : 40 parts and their copolymeriza-tion temperature and time were changed to 420 C and 2 hours, respectively, to obtain a reaction procuct. This reaction product had a melting point of 238 C and a weight-average molecular weight (~w) of 1400 and contained no ~uinoline insoluble.
~Second step) The FCC slurry oil obtained in Reference Exam-ple 2 was treated in an autoclave for 1 hour at 430 C in a nitrogen atmosphere at an antogenic pressure of 95 kg/cm2 (hydrogen partial pressure was 21 kg/cm2~; then, the 320 C or lower fraction was removed under a reduced pressure of 10 mmHg; and the resulting pitch was heated for 3 minutes at 450 C to obtain a heat-treated pitch having a melting point of 251 C, a softening point of 260 C and a quinoline insoluble content of 5 %.
(Third step) The same procedure as in Example 24 was repeat-ed except that the feeding ratio of the raction product obtained in the above first step and the heat-treated pitch obtained in the above second step were 40 parts :
60 parts and the melt mixing tempera-ture and time were 380 C and 30 minutes, respectively, to obtain a silicon-containing reaction product. The reaction product had an optical isotropy, a xylene insoluble content of 39 %, a weight-average molecular weight (~w) of 1210, a silicon content of 8.2 ~ and a melting point of 258 C.
Example 26 The silicon-containing reaction products ob-tained in Examples 23 and 24 were used as a spinning dope and subjected to melt spinning using anozzle of 0.3 mm in diameter. The resulting precursor fibers were cured at 300 C in an air current and pyrolyzed at 1300 C in an argon current to obtain carbonized inorganjic fibers.
The fiber obtained from the Example 23 dope had a dia-meter of 11 ~, a tensile strength of 288 kg/mm2 and a tensile modulus of elasticity o-E 24 t~mm2. The fiber obtained from -the Example 24 dope had a diameter of 9 ~, a tensile strength of 261 kg/mm2 and a tensile modulus of elasticity of 21 t/mm2 Observation by a scanning type electron micro-scope indicated that the both fibers had a sectional structure similar to the radial structure preferably used in pitch fibers and, in the two fibers, the mesophase component which had been present in the respective dopes was orientated to the fiber axis direction by the spin-ning, curing and pyrolyzing procedures.
Example 27 (First step) 170 g of the FCC slurry oil obtained in Refer-ence Example 2 was heated to 420 C in a nitrogen gas current to remove the 420 C fraction. The residue was filtered at 150 C to remove the portion which was not in a molten state at 150 C, to obtain 98 g of a reforming pitch.
The xylene soluble portion was removed from the reforming pitch to obtain a xylene insoluble component in an amount of 60 %.
60 g of the xylene insoluble component was mixed with 25 g of the organosilicon polymer obtained in Reference Example 1 and 20 ml of xylene. The mixture was heated with stirring and, after distilling off xylene, subjected to a reaction for 4 hours at 400 C to obytain 58 g of a reaction product.
Infrared absorption spectrum analysis indicated that in the reaction product there occurred the decrease of the Si-~ bond (IR: 2100 cm~l) presen-t in organosilicon polymer and the new forma-tion of Si-C (this C is a carbon of benzene ring) bond (IR: 1135 cm~l~. Therefore, it 5~J

became clear that the reaction product contained a struc-ture in which part of -the silicon atoms of organosilicon polymer bonded directly with a polycyclic aromatic ring.
The above reaction product contained no xylene insoluble and had a weight-average molecular weight of 1250 and a rnelting point of 2~8 C.
(Second step) 500 g oE the FCC slurry oil obtained in Refer-ence Example 2 was heated to 450 C in a nitrogen gas current to remove the 450 C fraction. ~he residue was filtered at 20C C to remove -the portion which was not in a molten state at 200 C and thereby to obtain 225 g of a reforming pitch.
The xylene soluble portion was removed from the reforming pitch to obtain 180 g of a xylene insoluble portion.
180 g of the xylene insoluble portion was subjected to a condensation reaction for 6 houxs at 400 C in a nitrogen current while removing the light frac-tions formed by the reaction, to obtain 96 g of a heat~treated pitch. This heat-treated pitch had a melting point of 262 C and a quinoline insoluble content of 7 ~.
The pitch was found by observing its polished surface by a polarizing microscope, to be mesophase pitch having an optical anisotropy of 96 ~.
(Third step) 40 g of the reaction product obtained in the first step and 80 g of the mesophase pitch obtained in the second step were rnelt mixed for 1 hour at 350 C in a nitrogen atmosphere to obtain a uniform silicon-contain-ing reaction poroduct.
The silicon-containing reaction product had an optical anisotropy of 58 %, a xylene insoluble content of 71 % and a melting point of 250 C and, when subjected to hydrogenation under mild conditions and then to measure-ment of weight-average molecular weight (Mw) by gel permeation chromatography (GPC), had a Mw of 1025.
The silicon-containing reaction product was heated to 1000 C in air; ~he resulting ash was subjected to al.]sali fusion and -then to a hydrochloric acid treat-ment, and dissolved in water; the resul-ting aqueous solution was measured Eor silicon concen-tration by a high frequency plasam emission spectrochemical analyzer ~ICP).
It indicated -that the si.licon content in the silicon-con-taining reaction product was ~.8 %.
Examp:Le 28 (First step) The same procedure as in Example 27 was repeat-ed except -that the xylene used as a solvent Eor washing the reforming pitch was changed to benzene, -the ratio oE
the organosil.icon polymer and the benzene insoluble portion was changed to 60 parts : 40 parts and the reac-tion conditions were changed to 420 C and 2.5 hours, to obtain a reaction product. This reaction product had a melting point of 256 C and a weitht-average molecular weight (Mw) of 1480.
(Second sted) The same procedure as in Example 27 was repeat-ed except that the xylene used as a solvent for washing the reforming pitch was changed to toluene and the heat treatment conditions were changed to 380 C and 12 hours, to obtain a meso phase-containing pi-tch. This pitch had a melting point of 248 C and a quinoline insoluble con-tent of 5 % and was found by observing its polished surface by a polarizing microscope, -to be a meso- phase pitch having an optical anisotropy of 75 ~.
(Third step) The same procedure as in Example 27 was repeat-ed except that -the feeding ratio of the raction product obtained in the above first step and the mesophase pitch obtained in the above second step was 40 parts : 60 parts and -the melt mixing conditions were 370 C and 30 minutes, to ob-tain a silicon-containing raction product.
This react:ion product ha.d a melting point of 255 C, a xylene insoluble conten-t of 58 %, an optical anisotropy of ~5 %, a weight-average molecular weight (Mw) of 1210 and a silicon con-tent: oE 8.5 %~
Example 29 The silicon-containing reaction products obtain-ed in Examples 27 and 28 were used as a spinning dope and subjected to me]t spinning using a nozzle of 0~3 mm in diameter. The resulting precursor fibers were cured at 300 C in an air current and pyrolyzed at 1300 C in an argon current to obtain carbonized inorganic fibers~ The fiber obtained Erom the F.xample 27 dope had a diameter of 12 ~ a tensile s-trength of 288 kg/mm and a tensile modulus of elasticity of 26 -t/mm2. The fiber obtained from the Example 28 dope had a diameter of 11 ~, a tensile strength of 270 kg/1~m2 and a tensile modulus of elasticity of 24 t/mm2.
Observation by a scanning type electron micro-scope indicated that the bothe fibers had a sectinalstructure similar to the radial structure preferably used in pitch fibers and, in the two finers, the mesophase components which had been present in the respective dopes was orientated to the fiber acis direction by the spin-ning, curing and pyrolyzing procedures.Example 30 (1) The mesophase pitch having an optical aniso-tropy of 95 %, obtained in the second step of Example 1 was allowed to stand at 350 C to separate and remove -the light portion by means of specifi.c gravity differance and thereby to obtain 80 g of the residue.
The reaction product obtained in the first step of Example 1 was melted and allowed to stand at 300 C
to separate and remove the light portion by means of specific gra-tivy difference and thereby to obtain 40 g of the residue.

The above two residues (80 g and 40 g) were mixed and allowed to stand for 1 hour at 350 c in a nitrogen atomosphere to obtain a uniform silicon-contain-ing reaction prsduct~ This reaction product had a melt-ing point oE 290 C and a xylene insoluble content of 70 ~. llereinafter, the reaction product is referred to as the matrix polymer Io (2) A two~dimensional plain weave fabric made fxom a commercially available PAN-based carbon fiber having a diameter of 7 ~m, a tensile strength of 300 kg/mm2 and a tensile modulus of elasticity of 21 t/mm2 was cut into discs each of 7 cm in diameter. The discs were impreg-nated wi-th a xylene slurry containing 30 ~ of the matrix polymer I and then dried to obtain prepreg sheets. In a mold, these prepreg sheets were laminated in a total sheet number of 30 with the fine powder of the matrix polymer I being packed between each two neighboring sheets and with the fiber direction of a sheet differing from that of the lower sheet by 45 C, and hot pressed at 350 c at a pressure of 50 kg/cm2 to form a disc-like molded material. This molded material was buried in a carbon powder bed for shape retention and heated to 300 C at a rate of 5 C/h in a nitrogen current and then to 1300 C to carbonize the matrix. The resulting composite material had a buld density of 1.60 g/cm3.
The composite material was immersed in a xylene slurry containing 50 % of the polymer I; the system was heated to 350 c under reduced pressure while distilling off xylene; then, a pressure of 100 kg/cm2 was applied to effect impregnation. Thereafter, the impregnated com-posite material was heated to 300 C in air at a rate of 5 c/h for curing and carbonized at 1300 C. This impreg-nation procedure was repeated three times to obtain a material having a bulk density of 1.95 g/cm3. The com-posite material had a flexural strength of 45 kg/mm2.Comparative Example 6 Using, as a matrix polymer, a petroleum-based heat-treated pitch having a softening point of 150 C and a carbon residue of 60 % f the procedure of Example 30 (2) was repeated to obtain a carbon fiber-reinforced carbon material. This material had a low bulk density of 1.67 g/cm3 and a low flexural strength of 15 kg/mm2.
Example 31 (1) 50 g of the organosilicon polymer obtained in Reference Example 1 was mixed with 50 g of a reforming pitch. The mixture was subjected to a reaction for 4 hours at 420 C to obtain a reaction product.
Separately, the reforming pitch was subjected to a reaction for 4 hours at 430 C to obtain a mesophase pitch.
The reaction product and the mesophase pitch were mixed at a 50-50 weight ratio and melted tc obtain a silicon-containing reaction product. Hereinafter, this reaction product is referred to as the matrix polymer II.
(2) A three-dimensional fabric made from a Si-~-C-O
fiber [Tyranno (registered trade name) manufactured by Ube Industries, Ltd.] was impregnated with a xylene solution containing 50 % of the matrix polymer II obtain-ed in (1) above, in an autoclave and, after removing xylene by distillation, was pressurezed at 100 kg/cm2 at 400 C to obtain a molded material. This molded material was cured at 280 C and pyrolyzed at 1300 C for carboni-zation. The above procedure was repeated four times to obtain a composite material having a bulk density of 1.88 g/cm3 and a flexural strength of 38 kg/mm2.
Example 32 A bundle of commercially available pitch-based carbon fibers each having a diameter of 10 ~m, a tensile strength of 300 kg/mm2 and a tensile modulus of elasticiy of 50 t/mm2 and arranged in the same one direction and a fine powder obtained by carbonizing the matrix polymer I
at 800 C were laminated by turns and hot pressed at 2000 3~3 - ~6 -C a-t 500 kg/cm2. The resulting composite ma-terial had a bulcl densi-ty of 2.n5 g/cm3 and a flexural streng-th of 58 kg/mm2.
Example 33 The composite materials of Examples 30, 31 and 32 and -the compjosite materia~ of Comparative Example 6 were each heated for 1 hour in an oven having an atmos-pheric temperature o:E ~00 C and then measured Eor flexural strength.
In the cornposite material of Comparative ~xam-ple 6,oxidative degradation progressed to such an extent that the strength measurement was impossible~ Meanwhile in -the composite material of Example 30, the flexural strength decreased by only 10 ~ and, in the composite materials of Examples 31 and 32, no strength decrease was seen.
Example 34 The powder of the matrix polymer I obtained in Example 30 was heated to 800 C in a nitrogen current to prepare a prefired material. This prefired material was finely ground to obtain a prefired powder. This prefired powder and an equal weight of the polymer I powder were subjected to wet mixing to obtain a powder. The powder was hot pressed at 350 C at 100 kg/cm2 to obtain a disc-like molded material having a diameter of 7 cm.
This molded material was buried in a carbon powder bed for shape retention and heated to 800 C in a nitrogen current at a rate of 5 c/h and further to 1300 c for carboni.zation. The resulting carbonaceous inorganic material had a bulk density OL- 1. 50 g/cm3~
This carbonaceous inorganic material was im-mersed in a xylene slurry containing 50 ~ of the polymer I and heated to 350 C under reduced pressure while distilling off xylene; a pressure of 100 kg/cm2 was appliea for impregnation; the impregnated materi.al was heated to 300 C in air at a rate of 5 C/h for curing r~

and then carbonized at 1300 C. This impregnation and carbonization procedure was repeated three rnore times to obtain a material having a bulk densi-ty of 1.95 g/cm3.
The material had a flexural strength of 21 kg/mm2. This carbonaceous inorganic material was pyrolyzed a-t 2500 c in argon, whereby the bulk densi-ty and flexural. strength improved to 1.9~ g/cm3 and 24 kg/mm2, respectively.
Also, the material had a flexural strength of 25 kg/mm2 at 1500 C in nitrogerl.
E~ample 35 A prefired powder was prepared from -the matrix polymer I in the same manner as in Example 34. 70 % of this prefied powder was added to 30n % of a powder of the matrix polymer Il obtained in Example 31 (1)~ They were molded and carbonized in the same manner as in Example 34 -to obtain a carbonaceous inorganic material having a bulk density o:E 1.67 g/cm3.
In the same manner as in Example 34, this material was immersed in a xylene slurry containing 50 ~
f the matrix polymer II and then carbonized; the impreg-nation and carbonization procedure was repeated three more times to obtain a carbonaceous inorganic ma-terial having a bulk density of 2.01 g/cm3. The material had a flexural strength of 23 kg/mm . ~hen this material was kept for 24 hours at 600 C in air, there was no decrease in weight or in strength.
Comparative Example 7 80 ~ of a synthetic graphite powder having a bulk density of 0.15 g/crn3 (under no load) was mixed with 20 % oE the mesophase pitch obtained in the second step of Example 1. The mixture was subjected to molding and carbonization in the same manner as in Example 34 to ob-tain a carbon material having a bulk density of 1.66 g/cm3.
The impregnation of the carbon material with mesophase pitch and the subsequent carbonization of -the .~d ~ ~ ~3 ~
- 8~ -impregnated carbon material was repeated four times in the same manner as in Example 34 to obtain a carbon material having a bulk density of 1.9~ g/cm3.
The carbon material had a flexural s-trength of 5.0 kg/mm . When the ma-terial was kept for 24 hours a-t 600 C in air t the weight decreased by 20 ~ and the material turned porous.
Comparative Example 8 The carbon material having a bul~ density of 1O66 g/cm3, obtained in Comparative Example 7 was covered with a metallic silicon powder and heated to 1500 C to give rise to melt impregna-tion J a reaction and sintering and thereby to obtain a carbon-carbon silicide composite material. The material had an improved flexural streng-th f 8.2 kg/mm2. However, when the material was measured for flrxural strength at 1500 c in nitrogen, the strength decreased to 3.0 kg/mm~ because the unreacted siliconn melted and consequently deformation occurred.
Example 36 (First step) 500 g of the FCC slurry oil obtained in Refer-ence Example 2 was heated for 1 hour at 450 C in a nitrogen gas current of 1 liter/min to distil off the 450 C fraction. The residue was fi]tered at 200 c to remove the portion which was not in a molten state a-t 200 c and thereby to obtain 225 g of a reforming pitch.
This reforming pitch had a xylene insoluble content of 75 % and an optical isotropy.
49 g of the pitch was mixed 21 g of the organo-silicon polymer obtained in Reference Example 1 and 20 ml of xylene. The mixture was heated with stirring and, after distilling off xylene, was subjected ot a reaction for 6 hours at 400 C to obtain 39 g of a precursor reaction product.
Infrared absorption spectrum analysis indicated that in the precursor reaction product there occurred the decrease of -the Si-H bond (IR: 2100 cm 1) present in organosilicon polyme.r and the new formation o:E Si-C (-this C is a carbon oE benzene ring) bond (IR: 1135 cm l)o Therefore, it became clear that the precursor reaction product contained a structure in which part of the silicon atoms of organosilicon polymer bonded directly with a polycyclic aromatic ring.
(Second s-tep) 39 g oE the precursor reaction product was mixed with 11 g of a xylene sol.ution containing 2.75 g (25 %) of tetraoctoxy-titanium [Ti(OC8H17)~. AEter distilling off xylene, the mi.xture was subjected to a reacti.on for 2 hours a-t 340 C to obtain 38 g of a reac-tion product.
The reaction product contained no ~ylene in-soluble and had a weight-average molecular weight of 1650 and a melting point of 272 C.
(Third step) 400 g of a FCC slurry oil was heated to 450 c in a nitrogen gas current to distil off the 450 C frac-tion. The residue was filtered at 200 C to remove the portion which was not in a molten state at 200 C, to obtain 180 g lighter reforming pitch.
180 g of the pitch was subjected ot a conden-sation reaction for 7 hours at 400 C in a nitrogencurrent while removing the ligh-t fractions formed by the reaction, to obtain 85 g of a heat-treated pitch.
The heat-treated pitch had a melting point of 268 C, a xylene insoluble content of 92 % and a ~uino-line insoluble content of 12 % and, when its polishedsurface was observed by a polarizing microscope, was a mesophase pitch having an optical anisotropy of 89 %.
(Fourth step) 15 q oE the raction product obtaine in the second step and 75 g of the mesophase pitch obtained in -the third step were melt mixed for 1 hour at 310 c to obtain a uni:E orm reaction product containing silicon and _ 9~ _ ti-tanium.
This ti-tanium-containing reaction product had an optical anisotropy of 66 901 a xylene insoluble of 74 %
and a melting point of 270 C and" when hydrogena-ted under mild conditi.ons and measured :~or weigh-t-average molecular weigh-t (MW) by gel permea-tion chromatography (GPC), had a ~w of 880.
The ti-tanium-containing reac-tion product was heated to 1200 c in air; the resulting ash was subjee-ted to alkali fusion and then to a hydroehlorie aeid treat-ment, and dissolved in water; -tne resul-ting aqueous solution was measured or silicon and titanium eoneentra-tions by a high frequeney plasma emission speetroehemieal ana]y%er (ICP~. It indiea-ted that the silieon and -tita-nium concentrations in teh titanium-eontaining reaetion product were 3.1 % and 0.1 %, respeetively.
Examples 37-42 Various titanium-eontaining reaction produets were obtained by varying the feeding ratio and reaetion conditions of the piteh, the organosilieon polymer and Ti(OC8H17)4 in the first and second steps of Example 36, the heat treatment eonndi-tions in the third step of Example 36 and the feeding ratio and melt mixing (melt eondensation) eonditions in the fourth step oE Example 36. The results are shown in Table 3 together wi-th the results of Example 36. In eaeh Example, the titanium-containing reaction produet obtained eontained silieon and titanium in amounts of 0.4-22.0 % and 0.01-3.5 %, respeetively, and had an optieal anisotropy.

Comparative Example 9 ~First step) 200 g oE the FCC oil slurry obtained in Refer-ence Example 2 was heated a-t 420 ~C for 2 hours in a nitrogen gas ~urrent of 1 liter/min to dis-til o-Ef -the 420 C fraction and thereby to obtain 11~ g oE a reforming pitch~ The pitch was dissolved in 500 ml oE xylene of 130 C to remove 69 g of the xylene insrluble portion.
The resulting xylene soluble portion (45 g~ of the pitch was mixed with 45 g of the organosilicon polymer obtained in Reference Example l; and the mixture was subjected to a copo:Lymerization reaction for 6 hours at 400 c to obtain 32 g oE a precursor reaction product.
(Second step) 200 g of the xylene soluble pi-tch component obtained in the first step was heat treated for 6 hours at 400 C in an inert atmosphere to obtain 41 g of a heat~treated pitch.
(Third step) 30 g of the copolymer obtained in -the first step and 60 g of the heat-treated pitch obtained in the second step were mixed for 2.5 hours at 300 C.
The resulting reaction product had a weight-average molecular weight (Mw) of 1750 and a silicon 25 content of 10.5 % but had a low melting point of 19~ C, a low xylene insoluble content of 11 % and an optical isotropy.
Comparative Example 10 100 g of the mesophase pitch obtained in the third step of Example 36 was mixed with 50 g of the organosilicon polymer obtained in Example 1, and the mixture was subjected to a reaction for 6 hours at 400 C
to obtain 79 g of a precursor reaction product. The copolymer had a melting point of 252 C, a silicon con-3~ tent of 15 % and a weight-average molecular weight ~Mw) of 1400 and contained no xylene insoluble and no meso-3 q~ ~ r~
- 9'1 -phase portion.
Example 43 39 g of the precursor reac-tion product obtained in -the first step of Example 36 was mixed with an ethanol-xylene solution containing 5.4 g (1.5 %) of tetrakisacetyl-acetonatozirconium. After distilling off the solvent, the mixture was subjected to a polymerization reaction for 1 hour at 250 C to obtain 39~5 g of a reaction product.
20 g of this reaction product and 50 g of a mesophase pitch prepared in the same manner as in Example 36 were melt mixed for 1 hour at 350 C to obtain 67 g of a reaction product containing silicon and zirconium.
This zirconium-containing reaction product had a melting point of 274 C, a xylene insoluble content of 69 % and a number-average molecular weight of 1050.
The silicon and zirconium contents in the reaction product were 4.1 % and 0.8 %, respectively.
Example 44 Using 60 g of the mesophase pitch obtained in Example 36 and 40 g of an organosilicon polymer, there was obtained 57 g of a precursor reaction product in the same manner as in Example 36.
40 g of this precursor reaction product was mixed with an ethanol-xylene solution containing 7.2 g of hafnium chloride. After distilling off ethanol and xylene, the mixture was subjected to a polymerization reaction for 1 hour at 250 C to obtain 43.5 g of a reaction product.
20 g of this reaction product and 80 g of a mesophase pitch were melt mixed for 1 hour at 350 C to obtain 96 g of a hafnium-containing reaction product.
This hafnium-containing reaction product had a melting point of 280 C, a xylene insoluble content of 76 % and a number-average molecular weight of 980.
The silicon and hafnium contents in the reac-~ 3 tion product were 3.6 % and 1~9 ~" respectively.
Example 45 The metal-containing reaction products obtained in EXamples 36, 3~, 39, 43 and 44 were used as a spinning dope and subjected -to melt spinning using a nozzle of 0.15 mm in diameter. The resultlng precursor fibers were cured at 300 c in an air current and pyrolyzed at 1300 c in an argon current to obt:ain carbonaceous in-organic Eibers. The Eiber obtained from Example 36 dope had a diameter of 9.5 ~, a tensile strength of 325 kg/mm2 and a tensile modulus of elasticity of 32 t/rnm2~ The fiber obtained from Example 38 dope had a diameter of 9.0 ~, a tensile strength of 318 kg/mm and a tensile modulus of elasticity of 36 t/rnm2. The fiber obtained from Example 39 dope had a diameter of 8.6 ~, a tensile streng-th of 360 kg/mm and a tensile modulus of elasticity of 33 t/mm . The Eiber obtained from the Example 43 dope had a diameter of 11.5 ~, a tensile strength of 340 kg/mm2 and a tensile modulus of elasticity of 34 t/mm2.
The fiber obtained from the Example 44 dope had a dia-meter of 12.0 ~, a tensile strength of 328 kg/rnm2 and a tensile modulus of elasticity of 38 t/mm2.
Observation of fiber section by a scanning type electron microscope indicated that each fiber had a coral-like radom structure, a random-radial structure (the radial occupied a basic structure) and a spiral-like onion structure and, in each fiber, the mesophase com-ponent which had been present in its dope was orientated to the film axis direction by the spinning, curing and pyrolyzing procedures.
Comparative Example 11 The reaction products obtained in Reference Examples 9 and 10 were subjected to spinning, curing and pyrolyzing in the same conditions as in Example 45, to obtain pyrolyzed fibers. The fiber obtained from the Comparative Example 9 dope had a diameter of 11 ~, a r tensile strength oE 120 kg/mm2 and a tensile modulus of elas-ticity oE 7~5 -t/mm2~ The Eiber obtained Erom the Comparative Example 10 dope had a diameter oE 10.5 ~, a tensile strength of 85 kg~mm~ and a ~ensile modulus of elasticity of 5.7 t~mm2.
The sections oE these Eibers containecl no orientat iOII S tructure.
Example 46 (First step) 700 g oE the FCC slurry oil obtained in Refer-ence Example 2 was heated Eor 0.5 hours at 450 C in a nitrogen gas current of 2 li-ters/min to distil off -the 450 C frac-tion. The residue was filtered at 200 C to remove the portion which was not in a molten state at 200 1~ C, to obtain 200 g a reforming pitch.
This reforming pitch contained 25 6 oE a xylene insoluble and was optically isotropic.
57 g of this pitch was mixed with 25 g of the organosilicon polymer obtained in Reference Example 1 and 20 ml of xylene. The mixture was heated with stirring to distil off xylene and subjected to a reac-tion for 4 hours at 400 C to obtain 57.4 g of a precursor reaction product.
Infrared absorption spectrum analysis indicated that in the precursor reaction product there occurred the decrease of the Si-H bond (IR: 2100 cm l)present in the organosilicon polymer and the new formation of Si-C (this C is a carbon of benzene ring) bond (IR: 1135 cm 1).
Therefore, it became clear that the precursor reaction product contained a structure in which part of the sili-con atoms of organosilicon polymer bonded directly with apolycyclic aromatic ring.
(Second step) 57.4 g of the precursor reaction produc-t was mixed with 15.5 g of a xylene solution containing 3.87 g (25 6) of tetraoctoxytitanium [Ti(OC,3H17)~]. After distilling off xylene, the mixture was subjected -to a 3~

reac-tion :Eor l hour at 340 C -~o obtain 56 g of a reac-tion product.
This reac-tion product contained no xylene insoluble and had a weight~averac;e molecular weight oE
5 1580r a melting point oE 258 ~C ancl a sof-tening point oE
292 C~
(Third step) 180 g of the ligh-ter reforming pitch obtained in Reference Example 2 was suhjected to a condensation reaction for 8 hours a-t A00 C while removing the light fractions formed by the reaction, to obtain 97r2 g oF a heat-treated pitch.
This heat~treated pitch had a melting point of 263 CI a softening point of 308 C~ a xylene insoluble 15 content of 77 % and a quinoline insoluble content of 31 and, by observing its polished surface by a polarizing microscope, was found to be a mesophase pitch having an optical anisotropy of 75 (Fourth step) 6~4 g of the reaction product obtained in the second step and 90 g of the mesophase pitch obtained in the third step wrer melt mixed for l hour at 380 C to obtain a uniform titanium-containing reaction product.
This titanium-containing reaction product had 25 an optical anisotropy of 62 ~ ~ a xylene insoluble content oE 68 QO~ a melting point of 264 C and a softening point of 307 C and , when hydrogena-ted under mild conditions and measured for weight-average molecular weight Mw by gel permeation chromatography (GPC), had a Mw of 860~
The titanium-containing reaction product was heated at 1200 c in air; the resulting ash was subjected to alkali fusion and then to a hydrochloric acid treat-ment, and dissolved in water; the aqueous solution was measured for silicon and titanium concentrations using a 35 high frequency plasma emission spectrochemical analyzer (ICP). It indicated that the silicon and titanium con-~a~

9~
tents in -the titanium-containing reaction product were 0.91 ~ and 0.06 ~, respectively.
Examples 47-54 Va.rious -titanium-containing reac-ti.on produc-ts were obtainecl by varying the :Eeeding ratio o.E the pitch, the organosilicon polymer and Ti(OC~H17)4 and the.ir reaction concli-tions in -the first and second steps of Example 46~ the heat treatment conditions in the third step oE Example 46 and the Eeeding ratio and -the melt mixing (melt condensa-tion) conditions in the fourth s-tep oE Example 46. The results are shown in Table 4 together wi-th the results of Example 46. In each Example~ the titanium-containing reaction product had an optical anirotropy.

~ 101 --Example 55 39 g of the precursor polymer obtained in Example 46 was mixed wi-th an ethanol-xylene solution containing 5.4 g (1.5 %) of tetrakisacetylacetonato zirconium~ After disti]ling off -the solvent, the mixture was subjected to a polymerization reaction for 1 hour at 250 c to obtain 39.5 g of a reaction product.
20 g of this reaction product and 50 g of a mesophase pitch prepared in the same manner as in Example 46 were melt mixed for 1 hour at 360 C -to obtain 67 g of a reaction product containing silicon and zir-conium.
This zirconium-containing reaction product had a melting point of 266 C, a xylene insoluble content of 54 ~ and a weight-average molecular weight of 1010.
The silicon and zirconium contents in the reaction product were 4.1 % and 0.8 ~, respectevely.
Example 56 Using 60 g of the pitch obtained in Example 46 and 40 g of an organosilicon polymer, there was obtained 57 g of a precursor reaction product in the same manner as in Example 46.
40 g of the precursor reaction product was mixed with an ethanol-xylene solution contaning 7.2 g of hafnium chloride. Af-ter distilling off xylene and ethanol, the mixture was subjected to a polymerization reaction for 1 hour at 250 C to obtain 43.5 g of a reaction product.
20 g of this reaction product and 30 g of a mesophase pitch were melt mixed for 1 hour at 350 C to obtain 96 g of a hafnium-containing reaction product.
This hafnium-containing reaction product had a melting point of 269 C, a xylene insoluble content of 60 % and a weight-average molecular weight of 930.
The silicon and hafnium contents in the reac-tion product were 3.6 % and 1.9 %, respectively.

S~ ..a~

Examp~Le 57 The metal-containing reaction products obtained in Examples ~6, 47, 54, 55 and 56 were used as a spinning dope and subjected to melt spinning using a nozzle of 0.15 mm in diameter. The resulting precursor fibers were cured at 300 ~C in an air current and pyrolyzed at 1300 C in an argon current to obtain carbonaceous inorganic fibers. The fiber obtained from the Example 46 dope had a diameter of 7.5 ~, a tensile strength of 358 kg/mm2 and 1~ a tensile modulus of elasticity of 32 -t/mrn2~ The fiber obtained from the Example 47 dope had a diameter of 9.5 ~, a tensile strength of 325 kg/rnm2 and a tensile modulus oE elasticity of 32 t/rnm . The fiber obtained from the Example 54 had a diameter of 8.5 ~, a tensile strength of 362 kg/mm2 and a tensile modulus of elasticity oE 34 t/mm2 The fiber obtained from the Example 55 dope had a diameter of 11.0 ~, a tensile strength of 350 kg/mm2 and a tensile modulus of elasticity of 34 t/mm2. The fiber obtained from the Example 56 dope had diameter oE 12.0 ~, a tensile strength of 340 kg/mm2 and a tensile modulus of elasticity oE 38 t/mm2.
Observation of fiber section by a scanning type electron microscope indicated that each Eiber had a coral-like random structure, a random-radial structure (th radial occupled a basic portion) and a spiral-like onion structure and, in each fiber, the meso phase com-ponent which had been present in its dope was orientated to the fiber axis direction by spinning, infusibilization and pyrolyzing procedures.
Example 58 (First step) 500 g of the FCC slurry oil obtained in Refer-ence Example 2 was heated to 450 c in a nitrogen gas current to distil off the 450 C fraction. The residue was filtered at 200 ~C to remove the portion which was not in a molten state at 200 ~C, to obtain 225 g of a t~

reforming pitch.
This reforming pitch con-tained a xylene in-soluble in an amount of 75 ~ and was ootically isotropic.
49 g oE the pitch was mixed with 21 g of the organos;licon polymer obtained in ReEerence Example 1 and 20 ml oE xylene, and the mixture was heated with s-tirring -to distil off xylene and then subjected to a reaction for 6 hours at 400 c to obtain 39 g of a precursor reaction product.
Infrared absorption spectrum analysis indicated that in the precursor reaction produc-t there occurred the decrease of the Si-H bond (IR: 2100 cm 1) present in organosilicon polymer and the new formation of Si-C (this C is a carbon of benzene ring) bond (IR: 1135 cm l) Therefore, it becsme clear that the precursor reaction product contained a structure in which part of the silicon atoms of organosilicon polymer bonded directly with a polycyclic aromatic ring.
(Second step) 39 g of the precursor reaction product was mixed with 11 g of a xylene solution containing 2.75 g (25 ~) of tetraoctoxyti-tanium [Ti~oc8Hl7)4]. ~fter distilling off xylene, the mixture was subjected to a reaction for 2 hours at 340 C to obtain 38 g of a reac--tion product This reaction product contained no xylene insoluble and had a weigh-t-average molecular weight of 1650 and a melting point of 272 c.
(Thirs step) 400 g of the FCC slurry oil obtained in Refer-ence Example 2 was heated -to 420 C in a nitrogen gas current to distil off the 420 C fraction. The residue was filtered at 150 c to remove the portion which was not in a molten state at 150 C, and then subjected to a polycondensa-tion reaction while removing -the light frac-tions formed by the reaction, to obtain 75 g of a heat-treated pitch. This hea-t-treated pi-tch had a mel-ting point of 275 C, a softening point: of 305 C~ a xylene insoluble content of 96 ~ and a quinoline insoluble content of 25 ~5 ancl, by observing its polished surface by a polarizing microscope, was found to be a mesophase pitch having an optical anisotropy of 95 %.
I'his mesophase pitch was subjected to hydro-genation for 1 hour at 360 c at a hydrocJen pressure of 100 kg~cm2 using a nichel-cobalt solid catalyst supported by zeolite. The resulting hydrogenation produc-t contain-ed no quinoline insoluble and, by oberving its polished surface by a polarizing microscope, was found to be an optically isotropic pitch~ This pi-tch was thermally stabilized by keeping for 30 minutes at 400 c in a nitrogen current, to obtain a heat-treated pitch. This heat-trdeated pitch contained no quinoline insoluble and had a melting point of 230 c, a softening point of 238 c and an optical isotropy. This pi-tch was made in-to a precursor fiber using a capillary having a diameter of 0.5 mm; the precursor fiber was cured at 300 c in air and pyrolyzed at 1000 C in a nitrogen current; the resulting fiber had an orientation to the fiber axis direction when its section was observed microscopically.
Therefore, the heat-treated pitch was potentially aniso-tropic~(Fourth step) 40 g of the reaction product obtained in the second step and 80 g of the heat-treated pitch obtained in the third step were melt mixed for 1 hour at 350 C to obtain a uniform titanium-containing reaction product.
This titanium-containing reactio product con-tained no xylene insoluble and had an optical isotropy, a melting point of 248 C and a softening point of 270 c.
The reaction product was measured for weight-average molecular weight (Mw) by gel permeation chromatography (GPC), which was lQ20.

The -titanium-containing reaction product was hea-ted to lOnO C in air, the resultirlg ash was subjected to al]cali Eusion and -then to a hydrochloric acid -trea-tment, and dissolved in water; the resulting aqueous solution was measured Eor metal concentrations by a high frequency plasma emission spectrochemical analyzer (ICP~. It indicated -that the silicon and titanium contents in the titanium-con-taining reaction products were 5.2 ~ and 0.2 %, respectively.
Exaple 59 (First step) 39 g of a precursor reaction product was obtain-ed in the same manner as in the first step of Example 58.
(Second step) 39 g of the precursor reaction product was mixed with an ethanol-xylene solution containing 5.4 g ~15 %) of tetrakisacetylacetonatozirconium. After distil-ling off the solvent, the mixture was polymerized for 1 hour at 250 C to obtain 39.5 g of a reaction product.
(Third step) A heat-treated pitch was obtained in the same manner as in Example 58 except that the conditions for converting to a meso phase were 420 C and 4 hours and hydrogenation was effected for 2 hours at 95 C using metallic lithium and ethylenediamine. This heat-treatedf pitch had a melting poing of 225 C and a soEtening point of 231 C,. and was found by the same method as in Example 58 to be potentially anisotropic.
(Fourth step) 20 g of the raction product obtained in -the second step and 5a g of the heat-treated pitch obtained in the third step were melt mixed for 1 hour at 350 c to obtain 67 g of a reaction product containing silicon and zirconium.
This zirconium-con-taining reaction product had a melting point of 242 c, a softening point of 268 C, a xylene insoluble content of 55 ~ and a weight-average q~ r ~

molecular weight of 960.
The silicon and zirconium contents in the reaction produc-t were ~.1 % and 0.8 ~, respectively.
Example 60 (First step~
Using 6n y of the pitch obtained in the Eirst step of Example 58 and 40 g of an organosilicon polymer, there was obtained 57 g of a precursor reaction product in the same manner as in E~ample 58.
(Second step) 40 g of the precursor reaction product was m,ixed with an ethanol-xylene solution containing 7.2 g oE
haEnium chloride. After distilling off ~ylene~ the mixture was polymerized for 1 hour at 250 C -to obtain 43.5 g of a reaction product.
(Third step) A heat-treated pitch was obtained in the same manner as in Example 58 except that the conditions for converting to a mesophase were 430 c and 1 hour and hydrogenation was effected for 1 hour at 420 C at a hydrogen pressure of 80 kg/cm2 using no catalyst. This heat-treated pitch had a melting point of 233 C and a softening point of 241 C and was conEermed by the same method as in Example 58 to be potentialy aniso-tropicO
(Fourth step) 20 g of -the reaction product obtained in the second step and 50 g of the heat-treated pitch obtained in the third step were melt mixed for 1 hour at 350 C to obtain 95 g of a reaction product containing silicon and hafnium.
This hafnium-containing reaction product had a melting point of 248 c, a softening point of 271 C, a xylene insoluble content of 63 ~ and a weight-average molecular weight of 890.
The silicon and hafnium conten-ts in the reaction product were 3.6 % and 1.9 %, respectively.

Example 6:L
l'he metal--containing reaction products obtained in Examples 58, 59 and 69 were used as a spinning dope and subjected to melt spinning using a nozzle of 0.15 mm in diameter. The resulting precursor fibers were cured at 300 C in an air current and pyrolyzed at 1300 c in an argon current to obtaln carbonaceous inorganic fibers.
These Eibers had diameters, tensile strenqths and tensile moduli of elasticity oE 9~0 ~, 360 kg/mm2 and 30 -t/mm2 in the case of the fiber obtained from the Example 58 dope, 10.9 ~, 365 kg/mm2 and 33 t/mm2 in the case of the fiber obtained from Example 59 dope and 11.2 ~, 351 kg/mm2 and 32 t/mm2 in the case of the fiber obtained from the Exxample 60 dope.
Observation of fiber section by a scanning type electron microscope indicated that each fiber had a coral-like random structure, a random-radial structure (the radial occupied a basic structure) and a spiral-like onion struc-ture and, in each fiber, the meso phase com-ponent which had been present in its dope was orientated to the fiber axis direction by the spinning, curing and pyrolyzing procedures.
Example 62 (First and second steps) These two steps were effected in the same manner as in the first and second steps of Example 36.
(Third step) 400 g of the FCC slurry oil obtained in Refer-ence Example 2 and 300 g of 1, 2, 3, 4--tetrahydroquinoline 30 were sub~ected to hydrogenation for 10 minutes at 450 c in an autoclave. Then, -the tetrahydroquinoline was distilled off to obtain a hydrogenated pitch.
The pitch was fed in-to a metallic container.
The container was immersed in a tin ba-th under a reduced pressure of 10 mmHg, and the pitch in the container was heat treated for 10 minutes at 450 C to ob-tain 62 g of a ~C~

hea-t-treated pitch.
The heat-treated pitch had a melting point of 230 ~c, a softening point of 238 ~C and a quinoline insoluble con-tent of 2~.
(Fourth step) ~ 0 g of the reaction product obtained in the second step and 80 g of the heat-treated pi-tch obtained in the third step were melt mixed for 1 hour a-t 350 C in a nitrogen atomosphere to obtain a unEorm titanium-containing reaction product.
This titanium-containing reaction product had an optical isotropy, a xylene insoluble content of 50 ~, a melting point of 254 C and a softening point of 271 C
and, when hydrogenated under mild conditions and measured for weight-average molecular weight (~w) by gel permea-tion chromatography ~GPC), had a ~w of 1100.
The titanium-containing reaction product was heated to 1000 C in air; the resulting ash was subjected to alkali fusion and then to a hydrochloric acid treat-ment, and dissolved in water; the resulting aqueoussolution was measured for metal concentrations using a high frequency plasma emission spectrochemical analyzer (ICP). It indicated that the silicon and titanium con-tents in the titanium~containing reaction product were 5-8 % and 0.2 ~, respectively.
Example 63 (First step) A precursor reactio product was obtained in the same manner as in the first step of Example 62.
(Second step) 39 g of the precursor reaction product was mixed with an ethanol-xylene solution containing 5.4 g (1.5 ~) of -tetrakisacetylacetonatozirconium. After distilling off the solvent, the mixture was polymerized for 1 hour at 250 C to ob~ain 39.5 g O-r a reaction product.
(Third step) The FCC slurry oil obtained in Reference Example 2 was hydrogenated in an autoclave for 1 hour at 350 C
at a hydrogen pressure of 80 ~g/cm2 using a nickel-cobalt sol:id catalyst suppor-ted by zeolite. The resul-ting oil was put under a reduced pressure of 15 mmlIg to distil off the 320 C or lower fraction. The resu]ting pitch was heated Eor 10 minutes at 440 c under a reduced pressure of 2 mmFlg to obtain a heat-treated p:i-tch having a melting point oE 248 C~ a softening point of 255 C and a ~uino-line insoluble content of 1 ~.
(Fourth step) 20 g of the reaction product obtained in thesecond step and 50 g of the heat-treated pitch obtained in the third step were melt mixed for 1 hour at 350 C to obtain 67 g of a reaction product containing silicon and zirconium.
This zirconium-contining reaction product had a melting point of 254 C, a softening point of 273 C, a xylene insoluble content of 61 % and a weight-average molecular weight (~w) -to 1010.
The silicon and zirconium contents in the reaction product were 4.0 % and 0.8 ~, respectively.
Example 64 (First step) Using 60 g of the pitch obtained in Example 62 and 40 g of an organosilicon polymer, there was obtained 57 % of a precursor reaction product in the same manner as in Example 62.
(Second step) 40 g of the precursor reaction product was mixed with an ethanol-xylene solution containing 7.2 g of hafnium chloride. After distilling off the solvent, the mix-ture was polymerized for 1 hour at 250 C to obtain 43.5 g of a reaction product.
(Third step) The FCC slurry oil obtained in Reference Exam-ple 2 was treated in an autoclave Eor 1 hour at 430 C in a ni-trogen atmosphere at an autogenic pressure oE 95 ]ig/cm2 (hydrogen par-tial pressure was 21 kg/cm2~. Then, the 320 C or lower fraction was removed under a reduced pressure of 10 INm Hg. The resulting pitch was heated for 3 minutes at 450 C under a reduced pressure of 10 mmHg to obtain a heat-trea-ted pitch having a melting point of 251 c, a softening point of 260 C and a quinGline insoluble content of 260 C~
(Fouxth step) 20 g of the reaction product obtained in the second step and 30 g oE the heat-treated pitch obtained in the third step were melt mixed for 1 hour at 350 C to obtain 96 g of a reaction product containing silicon and hafnium~
This hafnium-containing reaction product had a melting point of 253 C, a xylene insoluble content of 71 and a weight-average molecular weight of 870.
The silicon and hafnium contents in the reaction product were 3.6 % and 1.9 %, respectively.
Comparative Example 12 (First step) 200 g of the FCC slurry oil obtained in Refer-ence Example 2 was heated to 420 C in a nitrogen gas current to distil off the 420 C fraction to obtain 114 g of a reforming pitch. The pitch was dissolved in 500ml or xylene of 130 C. The xylene insoluble portion ~69 g) was removed and the resulting xylene soluble portion (45 g) of the pitch was mixed with 45 g of the organosilicon polymer obtained in Reference Example 1. The mixture was subjected to a copolymerization reaction for 6 hours at 400 c to obtain 32 g of a precursor polymer.
(Second step) 200 g of the xylene soluble pitch component ob-tained in the first step was heat treated for 2 hours at 400 ~C in a nitrogen gas current to obtain 65 g of heat-treated pitch which contained no quinoline insoluble and which had an optical isotropy.
(Third step~
30 g oE the precursor polymer obtained in the Eirst step and 60 g oE the heat-trea-ted pi-tch obtained in the second step were miced for 1 hour at 340 C. The resulting product had a weigh-t-average molecular weight ~w) of 1450 and a silicon con-tent of 9.8 ~ but had a mel-ting point oE 185 C~
Comparative Example 13 100 g of the reforming pitch obtained in Exam-pie 62 and 50 g of the organosilicon polymer obtained in Reference Example 1 were reacted for 6 hours at 400 C to obtain 79 g of a precursor polymer.
The precursor polymer had a melting point oE
252 C, a silicon content of 15 ~ and a weight-average molecular weight (~w) of 1400.
Examp~e 65 The metal-containing reaction products obtained in Examples 62, 63 and 64 were used as a spinning dope and subjected to melt spinning using a nozzle of 0.15 mm in diameter. The resulting precursor fibers were cured at 1300 C in an air current and pyrolyzed at 300 C in an argon current to obtain carbonaceous inorganic fibers.
These fibers had diameters, -tensile strengths and tensile moduli of elasticity of 9.5 ~, 345 kg~mm2 and 32 t/mm2 in the case of the Eiber obtained from the Example 62 dope, 12.0 ~, 350 kg/mm2 and 34 t/mm2 in the case of the fiber obtained from the Example 63 dope and 12.5 ~, 330 kg/mm2 and 33 t/mm2 in the case oE the fiber obtained from the Example 64 dope.
Observation of fiber section by a scanning type electron microscope indicated that each fiber had a coral-like random structure, a random-radial structure (the radial occupied a basic portion) and a spiral-like onion structure and, in each fiber, the meso-phase com-ponent which had been present in its dope was orientated to the -tiber axis direction by the spinning, curing and pyroly 2 ing procedures~
Comparative Example 14 rrhe polymers obtained in Compara-tive Examples 12 and :L3 were subjected to spinning, curing and pyrolyz-ing under the same conditions as in Example 65, to ob-tain pyrolyzed Eibers~ These Eibers had diameters, tensile strength and tensile moduli of elasticity oE 17 ~, 95 kg/mm2 and 6.0 t/mm2 in the case of the fiber obtained from -the Comparative Example 12 dope and 16 ~, 75 kg/rnm2 and 5.0 t/mm2 in the case of the fiber obtained from -the Comprative Example 13 dope. The sec-tion of each fiber contained no orientation structure.
Example 66 (First step) 500 g of the FCC slurry oil obtained in Refer-ence Example 2 was heated to 450 ~C in a nitrogen gas current to distil off the 450 c fraction. The residue was filtered at 200 c to remove -the portion which was not in a molten state at 200 C, to obtain 225 g of a iighter reforming pitch.
From this reforming pitch was removed the xylene soluble to obtain 180 g of an organic solvent in5Oluble (1).
49 g of the organic solvent insoluble (1) was mixed with 21 g of the organosilicoan polymer obtained in Reference Example 1 and 20 ml of xylene. The mixture was heated with stirring to distil off xylene and then subject-ed to a reaction for 4 hours at 400 C to obtain 48 g ofa predursor reaction product.
Infrared absorption spectrum analysis indicated that in the precursor reaction product -there occurred the decrease of the Si-H bond (IR: 2100 cm~l) presen-t in organosilicon polymer and the new formation of Si-C (this C is a carbon of benzene ring) bond (IR 1135 cm~l).

Therefore, it became clear that the precursor reaction product contained a structure in which par-t oE the silicon atoms oE organosilicon polymer bonded dîrec-tly with a polycyclic aromatic ring.
tSecond step~
50 g oE the precursor reaction product was mixed with a 11 g of xylene solution containing 4.0 g (25 %) of tetraoctoxytitanium [Ti(OC8~17)~l]. After dis-tilling off xylene, the mix-ture was subjeeted -to a reae~
tion for 2 hours at 340 C to obtain 49 g of a reaction product.
This reaction product contained no xylene insoluble and had a weight-average molecular weight of 1710 and a melting point of 275 C.
(Third step) 180 g of the organic solvent insoluble ~1) obtained in the first step was subjected to a polyeonden-sation reaetion for 6 hours at 400 c in a nitrogen eurrent while distilling off the light fraetions formed by the reaction, to obtain 96 g of a heat-treated pitch.
The heat-treated pitch had a melting point of 262 C and a quinoline insoluble eontent of 7 % and, when its polish-ed surface was observed by a polarizing mieroseope, was a mesophase piteh having an optical anisotropy of 96 %~
(Fourth step) 40 g of the reaction product obtained in the second step and 80 g of the mesophase pitch obtained in the third step were melt mixed for 1 hour at 350 C in a nitrogen atmosphere to obtain a uniform -titanium-contain-ing reaetion produet.
This titanium-eontaining reaetion product had an optieal anisotropy of 61 %, a xylene insoluble eon-tent of 75 %, a melting point of 263 C and a softening point of 272 C and, when hydrogenated under mild conditions and measured for weight-average molecular weight (~w) by gel permeation chromatography (GOC), had a ~w of 1045.

This titanium-containing reaction product was heated to 1000 C in air, the resul-ting ash was subjected -to alkali fusion and then to a hydrochloric acld trea-t-ment , and dissolved in water; the resulting- aqueous solution was measured for metal concentra-tions using a high frequency plasma emission spec-tro-chemical analyzer (ICP)~ It indicated that the silicon ancl titanium con-tents in the titanium-containing reaction product were 4.8 % and 0.18, respectively.
Example 67 (First step) A precursor reaction product was obtained in the same manner as in the first step of Example 66.
(Second step) 39 g of the precursor reaction product was mixed with an e-thanol-xylene solution containing 5.4 g (1.5 %f) of ~etrakisacetylacetonatozirconium. After distilling off the solvent, the mixture was polymerized for 1 hour at 250 ~C to obtain 39.5 g a reaction product.
(Third step) A mesophase pitch was obtained in the same manner as in Example 66 except that the solvent used -Eor washing the reforming pitch was toluene and the heat treatment conditions were 380 C and 18 hours, The mesophase pitch had a melting point of 248 C and a quinoline insoluble of 5 % and, when its polished surface was observed by a polarizing microscope, had an optical anisotropy of 75 %.
(Four-th step) 20 g of the reac-tion product obtained in the second step and 50 g of the meso phase pitch obtained in the third step were melt mixed for 1 hour at 350 CC to obtain 67 g of a reac-tion product containing silicon and zirconium.
This zirconium-containing reaction product had 'ie~, a melting polnt of 258 ~C, a softening point of 270 C, a xylene insoluble content oE 72 % and a weight-average molecular weight ~w) of 960.
The silicon and zirconium contents in the reaction product were 4.1 % and 0.8, respectively.
Example 68 (First step~
Using 60 g of the organic solvent insoluble (1) obtained in Example 66 and 40 g of an organosilicon polymer, there was obtained 57 g of a precursor reaction product in the same manner as in Example 66.
(Second step) 40 g of -the precursor reaction product was mixed with an ethanol-xylene solution containing 7.2 g of hafnium chloride. A-f-ter distilling off xylene, the mixture was polymerized for 1 hour at 250 C to obtain 43.5 g of a reaction product.
(Third step) A mesophase pitch was obtained in the same manner as in Example 66 except that the solvent used for washing the reforming pitch was benzene and the heat treatment conditions were 420 C and 4 hours. This mesophase pitch had a melting point of 256 C and a quinoline insoluble content of 7 % and, when i-ts polished surface was observed by a polarizing microscope, had an optical anisotropy of 80 %.
(Fourth step) 20 g of the reaction product obtained in the second step and 80 g of the mesophase pitch obtained in the third step were melt mixed for 1 hour at 350 C to obtain 97 g of a reaction product containing silicon and hafnium. This hafnium-containing reaction product had a melting point of 260 C, a xylene insoluble content of 79 ~ and a weight-average molecular weight of 920.
The silicon and hafnium contents in the react-ion product were 3.6 % and 1.9 %, respectively.
Example 69 The metal-con-taining reaction products obtained in Examples 66D67 and 68 were used as a spinning dope and subjected to melt spinning using a nozzle of 0.15 r.lm in diameter. The resulting precursor fibers were cured at 300 C in an air current and pyrolyzed at 1300 ~C in an argon current to obtain carbonaceous inorganic fibers.
These fibers had diameters, tensile streng-ths and tensile moduli of elasticity of 9,5 ~, 340 kg/mm2 and 32 t/mm2 in the case of the fiber obtained from the Example 66 dope, 11.1 ~, 348 kg/mm2 and 34 t/m2 in the case of the fiber obtained from the Example 67 dope and 11.5 ~, 332 kg/mm2 and 32 t/mm2 in the case of the fiber obtained from the ~xample 68 dope.
observation of fiber section by a scanning type electron microscope indicated that each fiber had a coral-like random structure, a random-radial structue (the radial occupied a basic portion) and a spiral-like onion structure and, in each fiber, the mesophase com-ponent which had been present in its dope was orientated to the fiber axis direction by the spinning, curing and pyrolyzing procedures.
Example 70 (1) 35 g of the raction produet ob-tained in the second step of Example 36 and 70 g of the mesophase pitch obtained in the third step of Example 36 were melt mixed Eor 1 hour at 350 C in a nitrogen atmosphere to obtain a uniform reaetion product eontaining silicon and titanium.
This reaction product had a melting point of 272 C and a xylene insoluble content of 59 %. Herein-after the reaction product is referred to as the matrix polymer III.
(2) A two-dimensional plain weave Eabric made from a commercially available P~N-based carbon fiber having a diameter oF 7 ~m; a tensile strength of 300 kg/mm and a tensile modulus of elasticity oE 21 t/mm was cut into discs of 7 cm in diameter. The discs were impregnated with a xylene slurry containing 30 ~ of -the matrix poly-mer III and -then dried to ob-tain prepreg sheets. In a die, these prepreg sheets were laminated in a ~otal sheet number oE 30 with the Eine powder of the matrix polymer III being packed between each two neighboring sheets and with the Eiber direction of a sheet differing from that Of -the lower sheet by 45 , and hot pressed at 350 C a-t a pressure of 50 kg/cm to form a disc--like molded material. This molded material was buried in a carbon powder bed shape reten-tion and heated to 800 C at a rate of 5 C/h in a nitrogen current and then to 1300 C to carbonize the matrix. The resulting composite ma-terial had a bulk density of 1.67 g~cm .
The composite material was immersed in a xylene slurry containing 50 % of the matrix polymer III; the system was heated to 350 C under reduced pressure while dis-tilling off xylene; then, a pressure of 100 kg/cm was spplied to effect impregnation. Thereafter, the impreg-nated composite material was heated to 300 C in air at a rate of 5 C/h for infusibilization and carbonized at 1300 C. This impregnation procedure was repeated three times to obtain a material having a bulk density of 2.05 g/cm . The composite material had a flexural strength of 55 kg/mm .
Comparative Example 15 Using, as a matrix polymer, a petroleoum-based heat-treated pitch having a softening point of 150 C and a carbon residue of 60 ~, there was obtained a carbon fiber-reinforced carbon material, in the same manner as in Rxample 70. The material had a bulk density of 1.71 g/cm and a flexural strength of 19 kg/mm .
Example 71 (1) 39 g of the precursor reaction product obtained 5~
- ll8 -in the first step of Example 36 was mixed with an ethanol-xylene solution containing 5.4 g (1.5 ~) of tetrakisacetyl-acetonato~irconium. AEter distilling off xylene and ethanol, the mixture was polymerized for 1 hour a-t 250 C
-to obtain 39.5 g oE a reaction produc-t.
20 g of the reaction product and 50 g of a meso phase pitch prepaxed in the same manner as in the fiest step of Example 36 were finely ground and melt-mixed and at 350 C to ob-tain a zirconium-containing reaction product This reaction product is hereinafter reEerred to as -the matrix polymer IV.
(2) A bundle oE commercially available pitch-based carbon fibers each having a diameter of 10 ~m, a tensile strength of 300 kg/mm and a tensile modulus of elasti-city of 50 t/mm and arranged in the same one direction and a fine powder obtained by carboni~ing the ma-trix polymer IV at 800 C were laminated by turns and hot pressed at 2000 c a-t 500 kg/cm . The resulting com-posite material had a bulk density of 2.05 and a flexuralstrength of 61 kg/mm .
Example 72 (1~ 57 g of a precursor reaction product was obtain-ed in the same manner as in the first step of Example 36 except that the amounts of the reforming pitch and the organosilicon polymer used were changed to 50 g and 50 g, respectively.
40 g of the precursor reaction product was mixed with an ethanol-xylene solution containing 7.2 g (1.5 %) of hafnium chloride. ~fter distilling oE-f xylene and ethanol, the mixture was polymerized for 1 hour at 250 ~C to obtain 43.5 g of a reaction product.
60 g of the reaction product and 40 g of a mesophase pitch were melt mixed at 320 C to obtain a hafnium-containing reaction product. This product is hereinaf-ter referred to as the matrix polymer V.

(2) A three-dimensional fabric made from a Si-M-C-o .Eiber [Tyranno (regis-tered trade name~ manufactured by Ube Illdustries, Ltd.] was mpregnated with a xylene solution containing 30 % of -the matrix polymer ~, in an S autocl.ave and, after distilling off xylene, was pressuriz-ed at 100 kg/cm at 400 C to obtain a molded material.
This rnolded material was cured at 280 ~C and pyrolyzed at 1300 C for carboniza-tion. The above procedure was repeated Eour times to obtain a composite material having a bulk density of 1.91 g/cm and a flexural strength of 42 kg~mm .
Example 73 The composite materials of Examples 70-72 and -the composite material of Comparative Example 15 were heated for 1 hour in an air oven of 500 C and then measured for flexural strength~
In the composite material of Comparative Example 15, oxidative deterioration progressed to such as extent that the measurement of flexural strength was i.mpossible.
In the composite material of Example 70, the flexural strength decreased by only 7 ~. In the composi-te materials of Examples 71 and 72, there was no decrease in flexural strength.
Example 74 The powder of the matrix polymer III obtained in Example 70 (1) was heated to 800 C in a nitrogen current to prepare a prefired material. This material was finely ground to obtain a prefired material powder.
The prefired material powder was set mixed with an equal weight of the powder of the matrix polymer III. The resulting powder was hot pressed at 100 kg/cm at 350 C
to obtain a disc-like molded material of 7 cm in dia-meter. This molded material was buried in a carbon powder bed for shape retention and heated to 800 C at a rate of 5 C/h in a nitrogen current and further to 1300 C for carboni2ation. The resulting carbonaceous inorganic ma-terial had a bulk density of 1.52 g/cm3.
The carbonaceous inorganic material was immers-ed in a xylene slurry containing 50 ~ of the matrix polymer ITI; the system was heated to 350 C under re~
duced pressure while distilling off xylene; then, a pressure of 100 kg/cm2 was applied to eEfect impreg-nation. ThereaEter, the impregnated composite materia]
was heated to 300 C in air at a rate of 5 C/h Eor curing and carbonizecl a-t 1300 C. This impregnation and carboniæation procedure was repeated three more times to obtain a material having a bulk density of 1.96 g/cm3.
The material had a Elexural strength of 23 kg/mm . When the carbonaceous inorganic material was fired at 2500 C
in argon, the bulk density and the flexural strength improved to 1.99 g/cm3 and 28 kg/mm2, respectively. The flexural strength at 1500 C in nitrogen was 29 kg/mm2.
Example 75 The matrix polymer IV obtained in Example 71 (1) was subjected to the same procedure as in Example 74 tG obtain a prefired powder. 70 ~ of this prefired powder was mixed with 30 % of the powder of the matrix polymer V obtained in Example 75 (1), and the mixture was molded and carbonized in the same manner as in Example 74 to obtain a carbonaceous inorganic material having a bulk density of 1.72 g/cm3.
In the same manner as in Example 74, this material was impregnated with a xylene slurry containing 50 % of the matrix polymer IV; the impregnated material was carbonized; this impregnation and carbonization procedure was repeated three more times to obtain a carbonaceous inorganic material having abulk density of 2.04 g/cm3. This material had a flexural strength of 28 kg/mm . When the material was kept for 24 hours at 600 C in air, there was no reduction in weight and strength.
Comparative Example 16 S~

- 12~ -80 ~ of a synthetic graphite powder having a bulk density oE 0.15 g/cm3 under no load was mixed wi-th 20 ~ of the meso phase pitch ob-tained in -the third step oE Example 36. The mix-ture was molded and carbonized in -the same manner as in Example 7~ to obtain a carbon mater:ial having a bulk density of 1.66 g/cm3.
Impregnation of this carbon material with mesophase pitch and subsequent carbonization were repeat-ed four times in the same manner as in Example 7~ to obtain a carbon material having a bulk density of 1.92 g/cm3/
The carbon material had a flexural strength of 5~0 kg/~m . When the material was kept for 24 hours at 600 C in air, the material showed a 20 % reduction in weight and became porous.
Comparative Example 17 The carbon material having a bulk density of 1.66 g/cm , obtained in comparative Example 16 was covered with a metallic silicon powder and heated to 1500 C to effect melt impregnation, reaction and sintering to obtain a carbon silicon carbide composite material. The material had an improved flexural strength of 8.2 kg/mm2.
When the material was measured for Elexural strength at 1500 C in nitrogen, the material caused deformation owing to the melting of unreacted silicon and showed a reduced flexural strength of 3.0 kg/mm2.
Example 76 The same silicon-containing reaction product as obtained in Example 30 (1) was used as a spinning material and subjected to melt spinning at 360 C using a metallic nozzle of 0.15 mm in diameter. The spun fiber was cured at 300 C in air and pyrolyzed at 1300 c in an argon a-tmosphere to obtain an inorganic fiber having a diameter of 10 ~m.
The Eiber had a tensile strength of 295 kg/mm2 and a tensile modulus of elasticity of 26 t/mm2 and, when i-ts breaking surface was observeci, clearly had a radial structure.
When -the Eiber was sublected to -thermal oxida-tion, ~here occurred substantially no weig~-t decrease up to 700 C and, at 800 C, only 5 ~ of the total weight was lost.
The inorganic fiber was used as a reinforcing agent for an epoxy resin of bisphenol A type to obtain a unidirectionally reinforced epoxy redin composite material lQ (Vf: 60 ~). This composite material had flexural streng-ths at 0 and 90 directions oE 195 kg/mm2 and 12.8 kg/mm2, respectively, which were far superior to the flexural strengths at 0 and 90 directions of 100 kg/mm2 and 3.5 kg/mm2 possessed by a unidirectionally reinforced epoxy resin composite material lVf: 60 %) using a conven-~ional pitch-based carbon fiber having a tensile strength of 280 kg/mm and a tensile modulus of elasticity of 55 t/mm .
Example 77 The precursor fiber (spun fiber) obtained in Example 76 was cured at 300 C in air and then pyrolyzed at 1400 C in an inert gas atmosphere to obtain an in-organic Eiber of 9.5 ~m in diameter. Observation by a transmission electron microscope indicated that, in the inorganic fiber, amorphous SiC and ~-SiC crystallites were uniformly dispersed in crystalline carbon.
The inorganic fiber consisted of a radial structure and partially a random structure and had a tensile strength of 232 kg/mm2 and a tensile modulus of elasticity of 30 t/mm2.
The inorganic fiber was used as a reinforcing agent for an epoxy resin of bisphenol A type to obtain a unidirectionally reinEorced epoxy resin composite material (Vf; 60 %). This composite material had flexural streng-ths at 0 and 90 directions of 150 kg/mm2 and 6.8kg/mm2, respectively.

r-~

Examples 78-80 (A) The residue (the 40-g residue) used in Example 30 (1) and obtained by mel-ting the reac-tion produc-t obtained in the first step of Example 1 and allowing it to stand at 300 C to remove the light por-tion by means of specific rgavity difference [the residue is hereinaf-ter referred to as the polymer (a)] and (~
the 95 % meso phase pitch obtained in the second step of Example 1 were melt mixed at various ratios at various temperatures to obtain three uniform silicon~-containing reaction products. These reaction products were made into inorganic Eibers in the same manner as in Example 76. The inorganic fibers were measured for mechanical properties. The results are shown in Table 5.
Table 5 _ _ _ I ~ I
olymer ~eso~ Mix- Mix- ~ylene ~ia- ~'ensil ~ensil (a) ?hase ing ng insolu- ~e-ter strength ~odulus of ?itch t.emp. time ble 2 ~lasticity _ __ (g) (g) (C) ~h) content (~m) (kg/mm ) (t/mm) ~mple 78 20 100 360 1 79 11 256 23 ~mple 79 60 60 320 1.5 45 12 238 18 ~mple 80 BO 40 300 1.5 25 12 200 15 Example 81 The same silicon-containing reaction product as obtained in Example 10 (3) was used as a spinning material 2Q and subjected to melt spinning at 360 C using a metallic nozzle of 0.15 mm in diameter. The resulting spun fiber was oxidized and cured at 300 C in air and -then pyrolyzed at 1300 C in an argon atomosphere to obtain an inorganic fiber of 8 ~m in diameter.

This inorganic fiber had a tensile strength of 320 kg/mm~ and a tensile modulus of elas-tici-~y of 26 t/mm2 ancl, when its breaking surface was observed, had a radial s~ructure The inorganic fiber was ground, subjected to alkali fusion and a hydrochloric acid treatment, dissolved in water, and then subjected to high frequency plasma emission spectrochemical analysis ~ICP). As a result, the inroganic fiber had a silicon content oE 0.95 ~.
The inorganic Eiber was oxidized in air wlth heating. No decrease in mechanical properties was seen even at 600 C. Thus, it was confirmed that the in-organic fiber was superior in oxidation resistance to commercially available carbon fibers which were burnt out 15 at 600 c.
The inorganic fiber was used-as a reinforcing agent for an epoxy resin of bisphenol ~ type to obtain a unidirectionally reinforced epoxy resin composite material (Vf: 60 %). This composite material had flexural 20 strengths at 0 and 90 directions of 210 kg/mm2 and 13.2 kg/mm2, respectively, which were far superior to the flexural strengths at 0 and 90 directions of 100 kg/mm2 and 3.5 kg/mm2 possessed by a unidirectionally reinforced epoxy resin composite matirial (Vf: 60 %~
using a conventional pitch-based carbon fiber having a tensile strength of 280 kg/mm2 and a tensile modulus of elasticity of 55 t/mm2.
Example 82 The precursor fiber (spun fiber) obtained in Example 81 was cured at 300 C in air and then pyrolyzed at 2400 C in an inert gas atmosphere to obtain an in-organic fiber of 7.1 ~m in diameter. Observation by a transmission electron microscope indicated that, in the inorganic fiber, ~-SiC crystallites were uniformly dis-persed in crystalline graphite.
This inorganic fiber consisted of a radial struc-ture and partially a random structure and had a tensile s-trength of 340 kg/mm2 and a high tensile modulus of elasticity of 55 t/mrn2.
The unidirectionally reinforcecl epoxy resin (bisphenol ~ type) composite ma-terial (Vf: 60 %) using the above inorganic -fiber as a reinjEorcing agent had flexural strengths at O abd 90 directions oE 205 kg/mm2 and 6.0 kg/mm2, respectively.
Examples 83~-86 The reaction product obtained in the first step of Example lO and the 75 % mesophase pitch obtained in the second step of Example 10 were melt mixed at various ra-tios at various temperatures to obtain four uniform silicon-containing reaction products. These reaction products were made into inorganic -'ibers in the same manner as in Example 81. The inorganic fibers were measured for mechanical proper-ties. The results are shown in Table 6.
Table 6 ~eac- Meso- Mix- ~ix- Silicon In- 3ia- Tensil Tensil ion phase ing ng content solu- ~e-ter strength ~dulus ?ro pitch temp. ime ble ~f luct elasti-(g) (g) (C) (h) (%) (%) (~m) (kg/mm2) (Ct/mm2) __ _ Example 83 20 100 360 1 2. 48 61 8 310 24 Example 84 60 60 3501.5 7.44 35.5 11 260 18 Example 85 80 40 3401.5 10.01 25 12 210 15 _ __ . _ _ Example 86 3 97 400 1 0.47 71 8 315 28 * The r_action product obtained in the first step Example 87 100 par-ts oE a bisphenol A type epoxy resin (XB
2879 A manufactured by Ciba Geigy Co.) and 20 parts of a dlcyandiamide curing agent (XB2879B manufac-tured by Ciba Geigy Co.) were mixed uniformly. The mixture was dissolv-ed in a mixed solvent of me-thyl cellosolve and acetone (1:1 by weight) to prepare a solution containing 28 ~ of the mixture.
The inorganic fiber havlng a silicon content of 0-95 ~, obtained in the first half of Example 81 (the fiber is hereinafter referred to as the inorganic fiber I1 was impregnated with the above solution and then taken off in one direction using a drum winder, and heated for 14 minutes at 100 C in a heat circulation oven to prepare prepregs of half-cured inorganic fibers arranged uni-directionally. The prepregs had a fiber content of 60 by volume and a thickness of 0.15 mm.
10 sheets of the prepregs were laminated with the $ibers arranged unidirectionally, and press molded at 7kg/cm for 4 hours at 170 C to obtain a unidirectional-ly reinforced epoxy resin composite matrial of 250 mm x 250 mm.
A test sample of 1.27 mm (width) x 85 mm (length) x 2 mm (thickness~ for measurement oE flexural strength was cut out from the above composite material. Using the test sample, a three-point bending test (span/width = 32) was conducted at a speed of 2 mm/min. The mechanical properties of the above composite material are shown below.
Tensile strength (kg/mm2) 170 Tensile modulus of elasticity (t/mm2) 16 Flexural strength (kg/mm2 232 Flexural modulus of elasticity (t/mm2) 16 ~ensile strength in direction perpendicular to fiber (kg/mm2) 6.7 Tensile modulus of elastici-ty in direction perpendicular to fiber (t/mm2~ 5.1 Flexural strength in direction perpendicular to fiber (kg/mm2) 9.2 Flexural modulus of elas-ticity in direction perpendicular to fiber (t/mm2~ 5.0 Interlaminar shear strength (kg/mm2) 9.0 Flexural shock (kg.cm/mm2) 255-Comparative Example 18 A carbon fiber-reinforced epoxy resin composite ma-tirial was produced in the same manner as in Example 87 : except that the inorganic fiber I was replaced by a high modulus pitch-based carbon fiber having a tensile strength of 280 kg/mm2, a tensile modulus of elasticity of 55 t/mm2 and a diameter of 10 ~. The composite material had a fiber content of 60 ~ by volume. The mechanical proper-ties of the composite material are shown below.
Tensile strength (kg/mm2) 150 Tensile modulus of elasticity (t/mm ) 23 Flexural strength (kg/mm2 100 Flexural modulus of elasticity (t/mm2) 12 Tensile strength in direction perpendicular to fiber (kg/mm2) 3.0 Tensile modulus of elasticity in direction perpendicular to fiber (t/mm2) 0.5 Flexural strength in direction perpendicular to fiber (kg/mm2) 3.5 Flexural modulus of elasticity in direction perpendicular to fiber (t/mm2) 0.5 Interlaminar shear strength (kg/mm2) 7.5 Flexural shock (kg.cm/mm2) 70 Comparative Example 19 A carbon fiber-reinforced epoxy resin composite matirial was produced in the same manner as in Example 87 except that the inorganic fiber I was replaced by a surface-treated high strength PAN-based carbon fiber having a tensile strength of 300 kg/mm2, a tensile modu-S~

lus of elasticity of 21 t/mm ancl a diameter of 7.5 ~.
The composite material had a fiber content of 60 ~ by volume and the Eollowing mechanical properties.
Tensile strength ~kg/mm ) 172 Tensile modulus of elasticity tt/mm ) 14 Flexural strength ~kg/~m 170 Flexural modulus of elasticity (t/mm ) 13 Tensile strength in direction perpendicular to fiber (kg/mm ) 4.5 Tensile modulus of elasticity in direction perpendicular to fiber (t/mm ) 0.88 Flexural strength in direction perpendicular to fiber (kg/mm ) 6.2 Flexural modulus of elasticity in deraction perpendicular to fiber (t/mm ) 0.87 Interlaminar shear strength (kg/mm ) 8.1 Flexural shock (kg.cm/mm ) 150 Example 8~
(1) 3 g of the reaction product obtained in Example 10 (1) and 97 g of the meso phase pitch obtained in Example 10 (2) were melt mixed for 1 hour at 400 c in a nitrogen atrmosphere to obtain a uniform silicon-contain-ing reaction product. This reaction product had a melt-ing point of 272 C, a softening point of 319 C and a 5 xylene insoluble content of 71 %.
The reaction product was used as a spinning material and subjected to melt spinning at 3~0 c using a metallic nozzle of 0.15 mm in diameter. The spun fiber was cured at 300 C in air and pyrolyzed at 2000 c in an 0 argon atmosphere to obtain an inorganic fiber II having diameter of 7.3 ~.
The inorganic fiber II had a tensile strength of 325 kg/mm and a high tensile modulus of elasticity of 41 t/mm .
The inorganic fiber II was ground, subjected to alkali fusion and then to a hydrochloric acid treatment, - 1~9 -and dissolved in wa-ter~ The resul-ting aqueous solution was subjected to high frequency plasma emission spectro-chemical analysis~ ~s a result, the inorganic fiber TI
had a silicon content oE 0.~7 %.
(2) The same procedure as in Example 87 was repeat-ed excep-t that -the inorganic fiber I was replaced by the inorganic Eiber II and the epoxy resin was replaced by a commercially available unsaturated polyester resin, to obtain an inorganic Eiber-reinforced polyester composite material having a Eiber content of 58 % by volume. This composite material had the following mechanical properties.
Tensile strength Ikgfmm ) 161 Tensile modulus of elas-ticity (t/mm ) 21 Flexural strength (kg/mm2 23~
Flexural modulus of elastici-ty (t/mm ) 205 Tensile strength in direction perpendicular to fiber (kg/mm2) 6.2 Tensile modulus oE elasticity in direction perpendicular to fiber (t/mm2) 5.5 Flexural strength in direction perpendicular to fiber (kg/mm2) 9.1 Flexural modulus of elasticity in direction perpendicular to fiber (t/mm ) 8.7 Interlaminar shear strength (kg/mm2) 9.0 Flexural shock (kg.cm/mm2) 251 Example 89 The same procedure as in Example 87 was repeat-ed except that the epoxy resin was replaced by a poly-imide resin manufactured by Ube Industries, Ltd., to obtain an inorganic fiber-reinforced polyimide composite material having a fiber content of 60 % by volume.
The composite material had the following mecha-nical properties.
Tensile strength (kg/mm2) 162 Tensile modulus of elasticity (t/mm ) 16 Flexural strength (kg/mm2 230 Flexural modulus of ela.sticity ~t/mm ) 16 Tensile strength in direction perpendicular to fiber (kg/mm 1 6.3 Tensile modulus of elasticity in direction perpendicular to :Eiber ~t/mm2) 4.9 E'lexural strength in direction perpendicular -to fiber (kg/mm2) 8.9 Flexural modulus of elast.icity in direction perpendicular to fiber (t/mm2) 5.0 Interlaminar shear strength (kg/mm2) 9.0 Flexural shock (kg.cm/~n2) 2Sl Example 90 100 parts of a bisphenol A type epoxy resin (XB2879A manufactured by Ciba Geigy Co.) and 20 parts of a dicyandiamide curing agent tXB2879B manufactured by Ciba Geigy Co.) were mixed uniformly. The mixture was dissolved in a mi~ea solvent of methyl cellosolve and acetone (1:1 by weight) to prepare a solution containing 2~ ~ of the mixture.
The same inorganic fiber I as used in Example 87 was impregnated with the above solution and then taken off in one direction using a drum winder, and heatedf for 14 minutes at 100 C in a heat circulation oven to prepare prepreg sheets of halfcured inorganic fibers arranged unidirectionally. Separately, a surface-treated carbon fiber (a PAN-based carbon fiber having a diameter of 7 ~, a tensile strength of 300 kg/mm2 and a tensile modulus of elasticity of 24 t/mm2) was subjected to the same treatment as above, to prepare prepreg sheets 0 of half-cured carbon fibers arranged unidirectionally.
The inorganic fiber prepreg sheets and the carbon fiber prepreg sheets were laminated by turns with the fibers arranged in one same direction and then hot pressed to obtain a hydrid fiber (inorganic fiber/carbon fiber)-reinforced epoxy resing composite material.
The composite material had a fiber content of t~

60 % by volume (content of inorganic Eiber = 30 % by volume and conten~ of carbon fiber = 30 % by volume).
The composite material had a tensile strength, a t:ensile modulus of elasticity and a flexural strength of 1~5 kg/mm2, 16.3 t~mm2 and 185 kg/mm2, respectively, at a 0 direction, a flexural strength of ~.3 kg/mm2 at a 90 direction, an interlaminar shear strength of 8.1 kg/mm2 and a Elexural shock of 22~ kg.cm/cm2.
Example 91 (1) 100 parts of a polydimethylsilane obtained by subjecting dimethylchlorosilane -to dechlorination conden-sation with me-tallic sodium was mixed with 3 parts of a polyborosiloxane. The mixture was condensed at 350 C in nitrogen to prepare a polycarbosilane having a main chain consisting mainly of a carbosilane unit represented by the formula (Si-CH2) (the silicon atom in the carbosilane unit has a hydrogen atom and a methyl group bonded thereto).
This polycatbosilane was mixed with a titanium alkoxide, and the mixture was subjected to crosslinking and polymeri-zation and 340 C in nitrogen to obtain a polytitanocarbo-silane consisting of 100 parts of the carbosilane unit and 10 parts of a titanoxane unit represeented by the formula (Ti-O). This polymer was melt spun, cured at 190 c in air and successively pyrolyzed at 1300 c in nitro-gen to obtain an inorganic fiber composed mainly ofsilicon, titanium, carbon and oxygen (titanbium content =
3 ~) and having a diameter of 13 ~, a tensile strength of 310 kg/mm and a tensile modulus of elasticity of 16 t/mm2 (monofilament method). The inorganic fiber was a Si-Ti-C-O fiber consisting of a mixed system of (A) an amorphous portion consisting of Si, Ti, C and O, (B) crystalline ultrafine particles each of about 50 ~ in diameter, of ~-SiC, TiC, a ~-SiC-TiC solid solution and TiCl x (O<x<l) and (C) an amorphous portion consisting of SiO2 and Tio2.
(2) The same procedure as in Example 90 was repeat-,3 ed except that the carbon flber was replaced by the Si-Ti-C-O fiber obtained in (1) above, -to obtain a hydrid fiber-reinforced epoxy resin composite materialO This composite ma-terial had a -fiber content oE 60 gO by volume (content of inorsanic fiber = 30 -~ by volume and content of Si-Ti-C-O Eiber = 30 ~ by volume). The composite material had a -tensile streng-th, a tensile modulus of elasticity and a flexural strength of 198 kg/mm2, 15.1 t/mm2 and 195 kg/mm2, respectively, at a 0 direc-tion, a Elexural strength of 12.0 kg/mm2 at a 90 direc-tion, an interlaminar shear strength of 11.5 kg/mm2 and a flexural shock of 280 kg.cm/cm .
Comparative Example 20 Using only a carbon fiber (PAN-based, diameter = 7 ~) and in the same manner as in Example 90, there were prepared prepreg shee-ts of half-cured carbon fibers arranged unifirectionally.
These prepreg sheets were laminated, with the fibers arranged in one same direction, and then hot pressed to obtain a carbon fiber-reinforced epoxy resin composite material. The composite material had afiber content of 60 ~ by volume. The composite material had a tensile strength, a tensile modulus of elasticity and a flexural strength of 150 kg/mm2, 14 -t/mm2 and 172 kg/mm2, respectively, at a 0 direction, a flexural strength of 6.2 kg/mm2 at a 90 direction, an interlaminar shear strength of 8.1 kg/mm2 and a flexural shock of 150 kg,cm/cm2.
Comparative Example 21 Using only the Si-Ti-C-O fiber obtained in Example 91 (1) and in the same manner as in Example9, there were prepreg sheets of Si-Ti-C-o fibers. These sheets were made into a Si-Ti-C-o fiber-reinforced epoxy resin composite material in the same manner as in Com-parative Example 20. The composite material had a fiber conten-t of 60 gO by volume. The composite material had a tensile modulus of elastici-ty of 11.3 t~mm . The other mechanical strengths of the material were about the same as those of Example 91.
Examples 92-9~
The same procedure as in Example 90 was repeat-ed except that the carbon fiber was replaced by an alumina fiber, a silicon carbide fiber or a glass fiber (their properties are shown in Table 7. They are hereinafter referred to as the second fiber for redinforcernen-t(s)), to obtain hydrid fiber-reinforced epoxy resin composite rnaterials. These composite fibers had a fiber content of 60 ~ by volume (inorganic fiber content = 30 % by volume, content of second fiber for reinforcement = 3d % by volume~.
The properties of the hydrid fiber-reinforced epoxy resin composite materials are shown in Table ~.
Table 7 Second fiber for ~ reinforcement Alumina Silicon E-glass Mechanical ~ fiber carbide fiber Properties _ fiber ~iameter (~) 9 15 10 Tensile strength (kg/mm )260 280 180 _ Tensile modulus 2f 25 20 7 elasticity (t/mm ) .~. ~ t~ 5,3 Table 8 ~ ~ Example Example Example Example¦
\ ~ 92 93 94 _ Second :Eiber \ :Eor rein- Alumina Silicon E-glass Mechanical \ Eorcement fiber carbide Eiber Properties --________=_ _ Eiber _ Tenslle strength (kg/mm ) 160 192 157 Tensile modulus ~E
elasticity (t/mm ) 16 15 11 . _ __ Flexural strength (kg/mm ) 188 214 178 Flexural modulus~of14 18 11 elas-ticity ~t/mm~) _ ~
Compre~sion strength185 191 165 Comparative Examples 22-24 Using an alumina fiber, a silicon carbide fiber or a glass fiber and in the same manner as in Example 90, -there were prepared alumina fibe prepreg sheets, silicon carbide prepreg sheets and glass fiber prepreg sheets.
Using these prepreg sheets and in the same manner as in Compatrative Example 20, there were prepared an alumina fiber-reinforced epoxy resin composite material, a silicon carbide fiber-reinforced epoxy resin composite material and a glass :Eiber-reinforced epoxy resin composite material, These composite ma-terials had a fiber content of 60 % by volume.

f~ t~8 The mechanical properti.es of the composite materials are shown in Table 9~ The mechanical proper--ties of the reinforclng second fi.bers us2d are shown in Table 7.
Table 9 ..._ Compara- ~ompara- Compara~
\ ~ Example tive Live tive \ ~ Example xample Exa24mPle \ Second fiber _ _ \ for rein- Al.umina Silicon E-glass Mechanical \ force- fiber carbide fiber Properties ~ ment fiber Tensile strength (kg/mm2) 130 170 120 _ Tensile modulus ~f elasticity (t/mm ) 14 12 4.5 Flexural strength (kg/mm2) 160 193 120 . _ Flexural modulus2of12 5 9 7 4 2 elasticity (t/mm ) (kg/Pmm~) 9 170 160 46 Example 95 Using, as reinforcing fibers, the inorganic fiber II and a silicon carbide fiber using carbon as its core, having a diameter of 140 ~l, a tensile strength of 350 kg/mm and a tensile modulus of elasticity and in the same mann~r as in Example 90, there was prepared a hydrid fiber-reinforced epoxy resin composite material. The composite material had a fiber content of 4~ % by volume (inorganic fibe II content = 30 ~ by volume, content of silicon carbide fibe using carbon as its core = 15 % by g q ~ ,~ r~ ~, volume).
The composite material had a tensile strength, a tensile modulus oE elastici-ty and a flexural strength - of 165 Icg/mm2, 25 t/mm2 and 210 kg/mm2, respec-tively~ at a 0 direction and a flexural strength of 6.1 kg/mm2 a-t a 90 direction.
Compara-tive Example 25 Using the silicon carbide fiber using carbon as its core, used in Exmaple 90 and in the same manner as in Example 90, there were prepared prepreg sheets of silicon carbide Eiber using carbon as it core. Using these prepreg sheets and in the same manner as in Comparative ~xample 20, there was obtained an epoxy resin composi-te material reinforced with a silicon carbide Eiber using carbon as its core. The composite material had a fiber content of only 33 % by volume becouse the silicon carbide fiber using carbon as lts core had a large diameter.
The composite material had a tensile strength, a tendile modulus of elasticity and a flexural strength of 140 kg/mm2, 23 t/mm2 and 195 kg/mm2 at a 90 direc-tion.
Example 96 Using, as reinforcing fibers, the inorganic fiber II and a boron fiber having a diameter of 140 ~, a tensile strength of 357 kg/mm and a tensile modulus of elasticity of elasticity of 41 t/mm2 and in the same : manner as in Example 90, there was prepared a hydrid fiber-reinforced epoxy resin composite material. This composite material had a fiber content of 50 ~ by volume (inorganic fiber II content = 30 ~ by volume, boron fiber content = 20 ~ by volume).
The composite material had a tensile strength, a tensile modulus of elasticity and a -flexural strength oE 175 kg/mm2, 25 t/mm2 and 210 kg/mm2, respectively, at a 0 direction and a flexural streng-th of 5.8 kg/mm2 at a 90 direction.

Comparative ExampLe 26 ~ sing only the boron Eiber used in Example 96 and in the same manner as in Example 90, there were prepared boron Eiber prepreg sheet:s. Then, a boron fibeer-reinforced epoxy resin composite material was obtained in -the same manner as in Comparative Example 20.
The composite material had a fibeer conten-t of only 31 by volume because the boron fiber had a large diameter.
The composite material had a tensile strength, a tensile modulus of elas-ticity andd a flexural strength of 154 kg/mrn2, 22 t/mm2 and 193 kg/mm2, respectively, at a 0 directior- and a Elexural strength or 3.8 kg/mm2 a-t a 90 direction.
Example 97 The same procedure as in Example 90 was repeat-ed except that the carbon fiber was replaced by an aramid fiber having a tensile strength of 270 kg/mm2 and a tensile modulus of elasticity of 13 t/mm2, to obtain a hydrid fiber-reinforced epoxy resin composite material.
The composite material had a fiber content of 60 % by volume (inorganic fiber content = 30 3 by volume, aramid fiber content = 30 % by volume).
The composite material had a tensile strength, a tensile modulus of elastlcity and a flexural strength f 156 kg/mm2, 12 t/mm2 and 158 kg/mm2, respective]y, at a Q direction and was significantly improved in strength and elastic modulus as compared with an aramid fiber-reinforced epoxy resin having a fiber content of 60 % by volume had a tensile strength, a tensile modulus of elasticity and a flexural strength of 95 kg/mm2, 5.3 t/mm2 and 93 kg/mm2, respectively, at a 0 direction.
The above composite material also had a flexural shock of 276 kg.cm/cm2 and did not substantially reduce the shock resis-tance of the aramid fiber which characterizes the fiber. (An aramid fiber-reinforced epoxy resin having a Eiber con-tent o-E 60 % by volume had a flexural shock of 3 ~

- l38 --302 kg.cm/cm r ) Example 98 To a ~-SiC powder having an average partiele diameter of 0.2 ~m were added 3 ~ Gf boron carbide and lO
~ oE a polytitanocarbosilalle powder, and -they were through-ly rnixed. This mixture and a bundle of the inorganie fibers I of 50 mm in length uniformly arranged in one direetion were laminated by -turns fo that the inorganic fiber I content in the resulting laminate became ~0 % by volume. The resultinq laminate was press molded at 500 kg/cm in a mold. The molded material obtained was heated to 1950 C in an argon atmosphere at a rate oE 200 C/hr and kept at that temperature for 1 hour to obtain an inorganic Eiber-reinforced silieon earbide eomposite sintered material.
Comparative Example 27 ~l) Dimethyldiehlorosilane was subjeeted to deehlori-nation eondensation with metallic sodium -to syn-thesize a polydimethylsilane. lO0 parts by weight of the polydi--methylsilane and 3 parts by weight of a polyborosiloxanewere mixed, and the mixture was subjected to eondensation at 3~0 C in nitrogen to obtain a polycarbosilane having a main ehain eonsisting mainly of a carbosilane uni-t represented by the formula (Si-H) (the silieon atom of the earbosilane unit has a hydrogen atom and a methyl group bonded thereto). The polyearbosilane was melt spun, eured at l90 C in air, and suecessively pyrolyzed at 1300 C in nitrogen to obtain a silicon earbide fiber eomposed mainly of Si, C and O, having a diameter of 13 ~, a tensile strength oE 300 kg/mm and a tensile modulus of elasticity of 16 t/mm .
(2) The same procedure as in Example 98 was repeat--ed except that the inorganie fiber I was replaced by the silicon carbide fiber produeed only frorn a polyearbosilane in (l) above, to obtain a silicon carbide Eiber-reinforeed silicon carbide composite sintered material.

-- 139 -`
Comparative Example 28 ~ sing a commercially available PAN-based carbon Eiber having a diame-ter oE 7.0 ~m, a tensile strength o 300 kg/mm and a tensile modulus of elasticity of 21 t/mm and in the same manner as in Example 98~ there was obtained a carbon fiber-reinforced silicon carbide com-posite sintered material.
Comparative Example 29 The same procedure as in Example 98 was repeat-ed excep-t that neither inorganic fiber nor polytianocarbo-silane powder was used, to obtain a silicon carbide sintered material.
Example 99 (1) The same spinning material as used in Example 15 88 ~1) was melt spun at 360 C using a me-tallic nozzle of 0.15 mm in diameter. The spun fiber was oxidized and cured at 300 C in air and pyrolyzed at 2500 C in an argon atmosphere to obtain an inorganic fiber III having a diameter of 7.2 ~.
This fiber had a tensile strength of 335 kg/mm and a tensile modulus of elasticity of 53 t/mm2.
The inorganic fiber III was ground, subjected to alkali fusion and then to a hydrochloric acid treatment, dissolved in water and then subjected to high frequency plasma spectrochemical analysis. As a result, the in-organic fiber III had a silicon content of 0.42 ~.
(2) The same procedure as in Example 98 was repeat ed except that the inorganic fiber III was used as a reinforcing fiber, to obtain an inorganic fiber-reinEorc-ed silicon carbide composite sintered material.
The mechanical strengths of the sinteredmaterials obtained in Example 93 and 99 and Comparative E~amples 27-29 are shown in Table 10. In Table 10 Elexural s-trength is a value when the measurement was made at a direction perpendicular to fiber.

~¢~

Table lO
Frexural strength (kg/mm ) ~ Reduction Deterio-_ _ _ Kic in flexu- ration ratio ral st- rate Room 800 C 1400 C rength (1950 ~) temp. (in air) (in nitrogen (800 C) (kg~m ___ _ _ _ ~ _ (~) sec ) EYample 98 57 48 645.l 5 OolO
Comparative 15 _ _ _ _ ~ple 27 _ _ _ Comparative 42 20 502.5 2S
Example 27 _ _ _ _ O~xrative 50 53 55 _ 70 _ _ Example 99 63 53 69 4.0 O.08 Example lO0 An X-Si3N4 powder having an average particle diameter of 0.5 ~m was thoroughly mixed with 2 % of alumina, 3 ~ of yttria and 3 % of aluminum nitride. The resulting powder and a bundle of the inorganic fibers I
of 50 mm in length arranged in one direction were laminat-ed by turns so that the fiber content in the resulting laminate became about lO % by volume. At this time, the inorganic fibers I were laminated in two directions of 0 and 90 ~ The laminate was pressed for 30 minutes at 300 kg/cm2 at 1750 C to obtain an inorganic fiber-reinforced silicon nitride composite sintered material.

The Elexural streng-th at room temperature and 1400 C, etc. of the sintered material are shown in Table 11 .
Comparative Example 30 The same procedure as in Example 100 was repeat-ed except that no inorganic fiber I was used, to obtain a sintered material. The results are shown in Table 11.
Table 11 _ Flexural ~trength _ Deterio-(kg/mn ) Reduction ration Kic in flexural rate ratio strength (1750~;) Room (1200 C) (kg~
temp.1400 C (%) sec ) Example 100 125 76 2.2 0.20 Comparative 120 45 _ 55 Example 30 _ 10 Example 101 To a powder (average particle diameter = 44 ,um) of a borosilicate glass (7740 manufactured by Corning Glass Works) were added 45 g6 by volume of chopped fibers of 10 mm in length obtained by cutting the inorganic 15 fiber 1. They were thoroughly dispersed in isopropyl alcohol to obtain a slurry. This slurry and a bundle of the inorganic fibers I arranged in one direction were laminated by turns, dried and hot pressed at 750 kg/cm for about 10 minutes at 1300 C in an argon atmosphere to 20 obtain an inorganic fiber-reinforced glass composite material. The results are shown in Table 12.
Comparative Example 31 The same procedure as in Example 101 was repeat-ed except that the inorganic fiber I was replaced by a 25 commercially available silicon carbide fiber, to obtain a ~t~ ?~
~ 2 glass ceramic. The resul~s are shown in Table ]2.
Table 12 _ Flexural ~trer.gth _ _ ~eterioration (]~g/mm ) Reduc-tion rate Kic in Ele~Yural (1300 C) (R~l~emperature) ratio strerlgth ~kg/~m2 seC-l (kg/mm ) ('300 C) (~
._ _ __ __ _ _ ___ E~ample 101 21.0 4 8 3 O.2 __ ~
Comparative Example 31 14.2 4 _ 1O50 ..._ _ Example 102 An alumina powder having an average particle diameter of 0.5 ~m was mixed with 2 ~ by weight of tita-nium oxide. To the mixture was added 15 ~ by volume of a spun Eiber of a silicon-containing reaction product ~this spun fiber was a precursor of the inorganic fiber I), and ln they were thoroghly mixed in an alumina-made ball millO
The precursor fiber had an average leng-th of about 0.5 mm. The mixture was sintered at 2000 c in an argon atmosphere using a hot press. The resulting sintered material was subjected -to a spalling test. Tha-t is, the sintered material was made into a shape of plate (40 mm x 10 mm x 3 mm); the plate was rapidly heated for 20 minutes in a nitrogen atmosphere in an oven of 1300 ~C; then, the plate was -taken out and subjected to forced air cooling Eor 20 minutes; this cycle was repeated until cracks appeared; thus, the cycle number in which cracks first appeared was examined.
The cycle number and mechanical strength of the sintered material are shown in Table 13.
Comparative Example 32 The same procedure as in Example 102 was repeat-ed except that no precursor fiber was used, to obtain a - 1~3 -sintered material.
The results are shown i.n Table 13 Table 13 _ _ _ Reduction Kic ratio in flexural Spalling test strength (cycle number) t800 C) ~%) __ ~ _ _~
Example 102 2.5 5 . . .
Comparative _ 90 Example 32 Example 103 A plain weave fabric of the inorganic fiber I
used in Example 87 was immersed in a methanol solution of a resol type phenolic resin (MRW 3000 manufactured by ~eiwa Kasei K.K.), pulled up, subjected to methanol removal and dried to obtain a prepreg sheet. The prepreg sheet was cut into square sheets of 5 cm x 5 cm;; the square sheets were piled up in a mold and pressed at 50 kg/cm at 200 C to cure the phenolic resin to obtain a molded material. The molded material was buried in a carbon powder and heated to 1000 C a-t a rate of 5 C/h in a nitrogen current to obtain an inorganic fiber-reinforced carbon composite material. The composite material was a porous material having a bulk density of 1.22 g/cm .
This compostie material was mi~ed with the mesophase pitch powder obtained in Example 1 (2), melted at 350 C in a nitrogen atmosphere in an autoclave, made vacuum to effect impregnation of the pores of the com-posite material with the mesophase pitch, pressurized at a 100 kg/cm2 to fur-ther effect impregnation, heated to 300 C at a rate of 5 C/h for curing, and carbonized at 1300 C. This impregnation with mesophase pitch and f~ Si~

carboni~ation procedure was repeated three more times to obtain a composite ma-tirial having a bulk density of 1.85 g/cm and a flexural strength oE 37 kg/mm~. The composite ma-terial had a fiber content (Vf~ of 60 % by volume~ ~Vf was 60 ~ by volume also in the following Example 10~.) Example 104 A graphite powder having an average particle diameter of 0.2 ~m arld -the same mesophase pitch powder as used in Example 103 were mixed at a 1:1 weight ratio.
The resulting mixed powder and the fabric of the in-organic fiber III obtained in Example 99 (1) were laminat-ed by turns and pressed at 100 kg/cm2 at 350 C to obtain a molded material. This molded material was subjected to four times of impregnation with mesophase pitch and carboniæation in the same manner as in Exmple 103, to obtain a composite material having a bulk densi-ty of 1.92 g/cm3 and a flexural strength of 41 kg/mm2. When the compos-tite material was heated to 2500 ~C in an argon atmosphere to graphitize the matrix, the flexural strength of the composite material improved to 51 kg/mm2.
Comparative Example 33 The same procedure as in Example 103 was repeat-ed except that there was used a commercially availlable P~N-based carbon fiber having a diameter of 7 ~m, a tensile strength of 300 kg/mm2 and a tensile modulus of elasticity of 21 t/mm2, to obtain a composite material.
The composite material had a bulk densLty of 1.83 g/cm3 and a flexural strength of 21 kg/mm2.
Comparative Example 34 Impregnation with mesophase pitch and carboniza-tion at 1300 C were repeated four times in ths same manner as in Example 104 e~cept that there was used a fabric of the silicon carbide fiber obtained in Compara-tive Example 27 (1), to obtain a co~posite material. The composite material had a flexural strength of 29 kg/mm2.
When this material was fur-ther pyrolyzed at 2500 ~C, the .;8 flexural strength decreased to 9 kg/mm2 and the fiber reinforcement effect: was lost completely Example 105 (1~ To 57.4 g of the reac}ion p{oduct of Example 10 ~1~ was added 15.5 9 of a xylene solution containing 25 (3.87 g) of tetraoctoxytitanium ~Ti(OC8H17)4]. After distilling off xylene, the residue was reacted for 1 hour at 340C to obtain 56 g of a reaction product.
The reaction product and the mesophase pitch obtained in Example 10 (2) were melt mixed at a ratio of 1:1 at 380C in a nitrogen atmosphere to obtain a polymer II.
(23 A two-dimensional plain weave fabric of the same inorganic fiber I as used in Example 87 was cut into discs of 7 cm in diameter. The discs were impregnated with a xylene slurry containing 30 ~ of the polymer II
and dried to prepare prepreg sheets. In a mold, these prepreg sheets were laminated in a total number of 30 with the fine powder of the polymer II being packed between each two neighboring sheets and with the fiber direction of a sheet differing from that of the lower sheet by 45, and hot pressed at 350C at a pressure of 50 kg/cm2 to obtain a disc-like molded material. This molded material was buried in a carbon powder bed for shape retention and heated to 800C at a rate of 5C/h in a nitrogen current and then to 1300C to carbonize the matrix. The resulting composite material had a bulk density of 1.19 g~cm3.
The composite material was immersed in a xylene slurry containing 50 ~ of the polymer II; the system was heated to 350C under reduced pressure while distilling off xylene; then, a pressure of 100 kg/cm2 was applied to effect impregnation. Thereafter, the impregnated com-posite material was heated to 300C in air at a rate of 5C~h for curing and carbonized at 1300C~ This im-preynation and carbonization procedure was repeated three r j ~ 146 ~
more times to obtain a composite material having a bulk density of l.96 g/cm3~ The composite material had a Elexural strength of 57 kg~mm2 Example 106 (13 To 39 g of the reaction product of Example lO
(13 was added an e~hanol-xylene solution containing 1.5 %
(5.4 g) of tetrakisacetylacetonatozirconium. After distilling off xylene, the residue was reacted for l hour at 250~C to obtain 39.5 g of a reaction product.
The reaction product and the same mesophase pitch as mentioned above were melt mixed at a l:l ratio at 380C in a nitrogen atmosphere to obtain a polymer III.
(2) The polymer III was prefired at l300C in nitrogen to obtain an inorganic material. 50 9 of this inorganic material was mixed with 50 g of a powder of the polymer III. The resulting mixture and a two-dimensional plain weave fabric of the inorganic fiber III obtained in Example 99 tl1 were piled up by turns and hot pressed at 400DC at lO0 kg/cm2 to obtain a molded material~ The molded material was carboniæed in the same manner as in Example 105. The resulting material was subjected to four times of ta) impregnation with the polymer III and ~b) carbonization, in the same manner as in Exa~ple l.
The resulting composite material had a bulk density of 2.03 g/cm3 and a flexural strength of 58 kg~mm2. When the composite material was pyrolyzed at 2200C in argon the bulk density and flexural strength improved to 2.06 g~cm3 and 63 kg~mm2, respectively.
Example 107 (l) The procedure of Example lO tl) was repeated except that the amounts of the reforming pitch and organosilicon polymer used were changed to 60 g and 40 g, respectively, to obtain 57 g of a reaction product.
To 40 g of this reaction product was added an ethanol-xylene solution containing 7.2 g (1.5 ~) of harfnium chloride. After disti;Lling off xylene, the residue was polymerized ~or 1 hour at 250C to obtain 43.5 g of a xeaction product.
The reaction product and the ~ame mesophase pitch as mentioned above were melt mixed at a 1:1 ratio at 380C in a nitrogen atmosphere to obtain a polymer IV.
(2) The procedure of Example 105 was repeated except that the polymer IV was used as a polymer for production of prepreg sheets, a polymer kor mold packing and a polymer for impregnation, to obtain a composite material. The composite material had a bulk density of 2.10 g~cm3 and a flexural strength of 54 kg/mm2.
Comparative ~xample 35 A carbon fiber-reinforced carhon material was obtained in the same manner as in Example 105 except that the inorganic fiber III as an reinforcing fiber was replaced by a commercially available PAN-ba~ed carbon fiber having a fiber diameter of 7 ~m, a tensile strength of 300 kg~mm2 and a tensile modulus of elasticity of 21 t/mm2 and the polymer III was replaced by a petroleum-based heat treated pitch having a softening point of 150C and a carbon residue of 60 %. This material had a low bulk density of 1.67 g~cm3 and a flexural strength of lS kg/mm .
Comparative Example 36 The silicon carbide fiber obtained in Com-parative Example 27 tl) and an equal weight mixture~ as a matrix material, of (a) synthetic graphite having a bulk density ~under no load) of 0.15 g/cm3 and (b) the same pitch powder as used in Comparative Example 35, were subjected to hot pressing in the same manner as in Example 106 to obtain a molded material The molded material was carbonized. The carbonized material was subjected to four times of (a) impregnation with the above pitch and (b) carbonization, to obtain a composite material having a bulk density of 1.90 g/cm3 and a r- ~3 -- 1~8 --flex-lral strength of 21 kg/mm2. It was tried to graphitize the composite material at 2200C, but the reinforcing fiber deteriorated and the strength of the composite material decreased to 5 kg/mm2 Example 108 The composite materials of Examples 105, 106 and 107 and Comparative ~xamples 35 and 36 were heated for l hour in an air oven of 600C and then measured for flexural strength. In the composite materials of Comparative Examples 35 and 36, oxida~ive deterioration took place to such an ex~ent as to allow no strength measurement. In the composite materials of Examples 1059 106 and 108, there was seen no strength reduction.
Example 109 ~l) 50 g of a reforming pitch was added to 50 g of the organosilicon polymer obtained in Reference Example l. The mixture was reacted for 4 hours at 4~0C to obtain 48 g o a reaction productO
Separately, a reforming pitch was reacted for 4 hours at 430C to obtain a mesophase pitch.
The reaction product and the mesophase pitch were melt mixed at equal weights to obtain a uniform silicon containing reaction product. The reaction product is hereinafter referred to as the polymer V.
(2) A two-dimensional plain weave fabric of the inorganic fiber I obtained in Example 87 (l) wa~ cut into discs having a diameter of 7 cm. The discs ~ere im-pregnated with a xylene slurry containing 30 % of the reaction product of Example lO (l) and dried to prepare prepreg sheetsO In a mold, these prepreg sheets were laminated in a total sheet number of 30 with the fine powder of the matrix polymer V being packed between each two neighboring sheets and with the fiber direction (angle) of a sheet advanced from that of the lower sheet by 45, and hot pressed at 350 at a pressure of 50 kg/cm to form a disc-like molded material. This molded r-~

material was buried in a carbon powder bed for shape retention and heated to 800C at a rate of 5C/h in a nitrogen current and then to 1300C to carbonize the matrix. The resulting composite material had a bulk density of 1.32 g~cm3.
The composi~e material was immersed in a xylene slurry containing 50 ~ of the product of Example 10 ~
the system was heated to 350C under reduced pressure while distilling oEf xylene; then, A pressure of 100 kgJmm2 was applied to effect impregnation. Thereafter, the impregnated composite material ~as heated to 300~C in air at a rate of 5C/h for curing and carbonized at 1300C. ~his impregnation and carboniæation procedure was repeated three more times to obtain a material having a bulk density of 1.95 g/cm3. ~he composite material had a flexural strength of 55 kg/mm .
Example 110 The silicon-containing reaction product ob-tained in Example 88 tl) was prefired at 1300C in nitrogen to obtain an inorganic material. 50 parts of this inorganic material and 50 parts of a powder of the polymer V were mixed. The mixture and a two-dimensional plain weave fabric of the inorganic fiber III obtained in Example 99 tl) were piled up by turns and hot pressed at 400C at 100 kgJcm2 to obtain a molded material. The molded material V was carbonized in the same manner as in Example 109. The carbonized material was subjected to four ~imes of ~a) impregnation with the polymer V and (b) carbonization, in the same manner as in Example 109. The resulting composite material had a bulk density of 2.02 g/cm3 and a flexural strength of 58 kg~mm2. When the composite material was pyrolyzed at 2200C in argon, the bulk density and flexural strength improved to 2.05 g~cm3 and 61 kgJmm , respectively.
Comparative Example 37 A carbon fiber-reinforced carbon material was t~

obtained in the same manner as in Example 109 except that the inorganic fiber I as a reinforcing fiber was chanqed to a commercially available PAN-based carbon fiber having a fiber diameter oE 7~m, a tensile strength of 300 kg/mm and a tensile modulus of elasticity of 21 t/mm2 and the polymer V was changed to a petroleum-based heat treated pitch having a softening point of 150C and a carbon residue of 60 %. The material had a low bulk density of 1.67 g/cm and a Elexural strength of 15 ~g/mm .
Comparative Example 38 The silicon carbide fiber obtained in Comparative Example 27 (1~ and an equal weight mixture of (a) snthetic graphite having a bulk density ~under no load) of 0.15 g/cm3 and (b) a powder of the same pitch as used in Comparative Example 37 were subjected to hot pressing in the same manner as in Example 110 to obtain a molded material. The molded material was carbonized and then subjected to four times of (a) impregnation with the above pitch and (b) carbonization, to obtain a composite material having a bulk density of 1.90 g/cm3 and a flexural strength of 21 kg/mm . It was tried to graphitize the composite material at 2200C, but the reinforcing fiber deteriorated and the strength decreased to 5 kg/mm2.
Example 111 The composite materials of Examples 109 and 110, and Comparative Examples 37 and 38 were heated for 1 hour in an air oven of 600C and then measured for flexural strength.
In the composite materials of Comparative Examples 37 and 38, oxidative deterioration took place to such an extent as to allow no strength measurement.
Meanwhile, in the composite material of Example 109, strength reduction was only 5 % and in the composite material of Example 110~ there was seen no strength reduction.

i?

Example 112 A fiber was produced using an apparatus of Fig.
lo FigO 1 is a schematic illustration showing an example of the apparatus used for production of a fiber for use in the composite material of the present inven-tion, wherein the numeral 1 is a treating tank, the numeral 2 is an ultrasonic applicator, the numeral 3 is a treating solution, the numeral 4 is a continuous fiber bundle, the numerals 5 and 10 are bobbins, the numerals 6 and 7 are movable rollers, the numerals 8 and 9 are pressure rollers, the numeral 11 is a blower, the numeral 12 is a drier and the numeral 13 is a stirrer.
250 g of silicon carbide fine particles (average diameter: 0.28/~m) was placed in a treating tank 1 containing 5,000 cc of ethyl alcoholn Ultrasonic vibration was applied by an ultrasonic applicator 2 to suspend the silicon carbide fine particles in ethyl alcohol and thereby to prepare a treating solution 3.
A continuous fiber bundle 4 of the same in-organic fiber I as used in Example 87 was unwound from a bobbin 5 and passed through a treating solution 3 with the passing time controlled at about 15 sec by movable rollers 6 and 7. ~During the passing, an ultrasonic wave was applied to the treating solution 3 and the solution 3 was stirred with air being blown.) Then, the continuous fiber bundle was pressed by pressure rollers 8 and 9, wound up by a bobbin 10, and dried at room temperature in air. In Fig. 1, the numerals 11 and 12 are a blower and a drier, respectively, and are used as necessary. The numeral 13 is a stirrer.
The fiber which had been black before the treatment had a grayish green color after the treatment.
Weighing of the fiber after the treatment indicated that 6 % by volume of the fine particles attached to the fiber.

Example 113 The same treatment as in Example 112 was re-peated except that as the treating solution in the treating tank 1 there was used a slurry ohtained by suspending 100 g of silicon carbide whiskers (average diameter: about 0.2~m, average length: about 100J~m~ and 250 g o silicon carbide fine particles (average particle diameter: 0O28f~m) in 5,000 cc of ethyl alcohol.
The fiber which had been black before the treatment had a grayish green color after the treatment.
Observation of the fiber after the treatment by an electron microscope (SE~) indicated that mainly fine particles attached to the surface of each continuous fiber and further mainly whiskers attached thereonto.
Weighing of the fiber after the treatment indicated that 9 % by volume of the fine particles and whiskers attached to the fiber.
Example 114 The same treatment as in Example 113 was re-peated except that as the continuous fiber there was usedthe inorganic fiber II obtained in ~xample 88 ~1), to obtain a fiber to which about 8 % of fine particles and whiskers had attached.
Example 115 A continuous fiber bundle 4 of the inorganic fiber I was treated in the same manner as in Example 112 except that as the treating solution there was used a suspensln obtained by suspending 100 9 of silicon nitride whiskers (average diameter: about 0.3/~m, average length:
30 about 200~ m) and 100 g of the above silicon carbide fine particles in 5,000 cc of water. As a result, about 4 %
by volume of the fine particles and whiskers attached to the continuous fine bundle 4.
Example 116 A continuous fiber bundle 4 of the inorganic fiber I was passed through a suspension obtained by stirring 100 9 of silicon carbide fine particles in 500 cc of ethanol, while applying am ultrasonic wave to the suspensionO Then, the fiber bumdle was passed through a suspension obtained by stirring 150 9 of silicon nitride whiskers in 500 cc of ethanolr in the same manne~ and dried. As a result, about 12 % by volume of the fine partlcles and whiskers attached to the fiber bundle.
Example 117 The silicon-containing reaction product ob-tained in the third step of Example 10 was finely groundand then pyrolyzed at 1300C in an argon current to obtain a fine powder having an average particle diameter of 0.5 m and consisting of crystalline carbon, amorphous carbon and an amorphous material composed mainly of Si-C-O. 100 g of this f ine powder was suspended in 500 cc of ethanol by stirring~ A continuous fiber bundle 4 of the inorganic fiber I was passed through the above suspension while applying an ultrasonic wave to the suspension. The fiber bundle was then passed through a suspension obtained by suspending 150 g of silicon nitride whiskers in 500 cc of ethanol by stirring, in the same manner and dried. As a result, about 10 % by volume of the f ine particles and whiskers attached to the fiber bundle.
Comparative Example 39 Using, as a continuous fiber, a commercially available acrylonitrile-based carbon fiber (HM-35), there was repeated the procedure of Example 112 to obtain a fiber to which a silicon carbide powder had attached, as well as a fiber to which silicon carbide whiskers had attached.
Example 118 Using the fiber of Example 112 and an aluminum matrix, there was prepared a unidirectionally reinforced FRM. The FRM had a fiber volume fraction (vf) of 50 %
and a flexural strength of 165 kg/mm2 (tne ROM value was 175 kg/mm2).

- 15~ --Comparative Example 40 Using the fiber to which a silicon carbide powder had attached/ obtained in Comparative Example 39 and an aluminllm matrix, there was prepared a unidirec-tinnally reinforced FRM. The FRM had a fiber volumefraction tv) of ~0 % and a Elexural strength of 130 kg/mm2. Therefsre, the strength was considerably low as compared with the ROM value tl60 kg/mm )~
Example 119 Using the fiber of Example 113 or 114 and~ as a matrix 7 aluminum containing 5 ~ in total of copper and n,agnesium, there were prepared two unidirectionally reinforced FRM's. These FRM's each had a fiber volume fraction of 50 %. Their flexural strengths were 170 kgJmm when the fiber of Example 113 was used and 165 kg/mm when the fiber of Example 114 was used, and were scarcely different from the ROM values ~175.0 kg/mm2~.
Comparative Example 41 Using the fibers of Comparative Example 39 and the matrix of Example 118, there were prepared two FRM's.
The FRM using the fiber to which a silicon carbide powder had attached, had a fiber volume fraction (Vf) of 60 ~
and a flexural strength of 125 kg/mm2 ~the ROM value was 160 kg/mm ~. The FRM using the fiber to which silicon carbide whiskers had attached, had a fiber volume frac-tion ~Vf) of 50 % and a flexural strength of 100 kg/mm2 ~the ROM value was 130 kg/mm ). In the both FRM's, the strengths were considerably low as compared with the ROM
values.
Example 120 The same inorganic fiber as used in Example 87 was unidirectionally arranged on a pure aluminum foil ~specified by JIS 1070) of 0.5 mm in thickness. Thereon was placed another aluminum foil of same quality and si~e. The laminate was subjected to hst rolling at 670C
to prepare a composite foil of fiber and alumin~m. The ~0~

composite foil was piled up in ,a total sheet number of 27, was allowed to stand for 10 minutes at 670C under vacuum, and then subjected to h~t pressing at 6~0C to obtain an inor~anic fiber-reinforced aluminum composite material.
The inorganic fiber was measured for initial deterioration rate ~kg~mm2.sec 1) and fiber strength reduction (%). The composite material was measured for tensile strength in fiber direction (kg/mM2), tensile 1~ modulus of elasticity in fiber direction ~t~n2), interlaminar shear strength ~kg~mm2), tensile strength in direction perpendicular to fiber (kg/mm2) and fatigue limit/tensile strength. The results are shown in Table 14. The Vf of the composite material was 30 ~ by volumeO
Comparative Example 42 A carbon fiber-reinforced aluminum composite material was prepared in the same manner as in Example 120 except that there was used, in place of the inorganic fiber used in the present invention, a commercially available PAN-based carbon fiber having a tensile strength of 300 kg~mm2 and a modulus of elasticity of 21 t/mm2. The carbon fiber and the composite material were measured for the above mentioned properties. The results are shown in Table 14. The Vf of the composite material was 30 % by volume.

Table 14 Comparative Example 1~ E~
Initial det~riora~ion rate ~kg~mm ~sec ) 0.9 3.2 Eiber strength reduction (%) 55 90 Tensile strength in 2 fiber direction (kg/mm ) 51 25 Tensile modu:Lus of elasticity in f~ber direction (t/mm ) 908 6.5 Interlaminar sh~ar strength ~kg/mm ~ 4.~ 2.2 Tensile strength in direction perpe~dicular to fiber (kg/mm ) 3.9 1.8 Fatigue limit~
tensile strength 0.38 0.25 Example 121 A fiber-reinforced metal was prepared in the same manner as in Example 120 except that there was used an aluminum alloy foil ~specified by JIS 6061). The inorganic fiber and the fiber-reinforced metal were measured for the above mentioned properties. The results are shown in Table 15.
C0mparative Example 43 A carbon fiber-reinforced aluminum composite material was prepared in the same manner as in Example 121 except that the inorganic fiber was replaced by a carbon fiber. The carbon fiber and the composite mate-rial were measured for the above mentioned properties.
The results are shown in Table 15.

Table 15 Comparative Example 121 Example 43 Initial det~riora~ion rate (kg~mm .sec ) 1.1 3.9 Fiber strength reduction ~%) 59 95 Interlaminar sh~ar strength tkg~mm ) 10.1 4.0 Tensile strength in direction perpe~dicular to fiber ~kgJmm ) 7.5 3.2 Fatigue limit~
tensile strength 0.39 OD25 Example 122 A plurality of the inorganic fibers I were arranged unidirectionally and coated with metallic titanium in a thickness of 0.1-10 ~ by the use of a thermal spraying apparatus. This coated inorganic fiber layer was piled up in a plurality of layers with a titanium powder being packed between each two neiyhboring layers. The laminate was press molded. The molded material was prefired for 3 hours at 520C in a hydrogen atmosphere and then hot pressed at 200 kg~cm2 at 1150C
for ~ hours in an argon atmosphere to obtain an inorganic fiber-reinforced titanium composite material~
The inorganic fiber was measured for initial deterioration rate (kg/mm2.sec 1) and fiber strength reduction ~%), and the composite material was measured for tensile strength in fiber direction (kg/mm2), interlaminar shear strength (kg/mm2), tensile strength in direction perpendicular to fiber ~kg~mm2) and fatigue limit/tensile strength. The results are shown in Table 16.

The tensile strength in fiber direction~ of the composite materiaL was 122 kg/mm , which was about t~o times the tensile strength of metallic titanium alone.
The Vf of the composite materiaL was 45 % by volume.
Comparati~e Example 4~
A carbon fiber reinforced titanium composite material was prepared in the ~ame manner as in Example 122 except that the inorganic fiber was replaced by a carbon fiber. The carbon fiber and the composite mate-rial were measured for the above mentioned properties~
The results are shown in Table 16.
Table 16 Comparative Exam~le 122 Example 44 Initial det~riora~ion rate (kyJmm .sec ) 1.0 3.7 Fiber strength reduction (%) 58 95 Tensile strength in fiber direction (kg/mm2) 122 52 Interlaminar sh~ar strength (kg/mm ) 12.1 4.7 Tensile strength in direction perpe~dicular to fiber (kg~mm ) 8.3 3O8 Fatigue limit/
tensile strength 0.33 0.20 Example 123 A plurality of the inorganic fibers I were arranged unidirectionally and coated with a titanium alloy (Ti~6Al-4V) in a thickness of 0.1-10 ~ by the use of a thermal spraying apparatus. This coated inorganic fiber layer was piled up in a plurality of layers with a titanium powder being packed between each two neighboring layers. The laminate was press molded~ The molded material was prefired for 3 hours at 520C in a hydrogen gas atmosphere and then hot prer,sed at 200 kg/cm2 at 1150C for 3 hours in an argon atmosphere to obtain an inorganic fiber-reinforced titanium composite material.
The inorganic fiber was measured for initial deterioration rate ~kg/mm2.sec 1) and fiber strength reduction ~%), and the composite material was measured for interlaminar shear strerlgth tkg/mm23, tensile strength in direction perpendicular to fiber (kg/mm2) and fatigue limit/tensile strength. The Vf of the composite material was 45 ~ by volume. The results are shown in Table 17.
Comparative Example 45 A carbon fiber-reinforced titanium composite material was prepared in the same manner as in Example 123 except that the inorganic fiber was replaced by a carbon fiber. The carbon fiber and the composite mate-rial were measured for the above mentioned properties.
The results are shown in Table 17.
Table 17 Comparative Example 123 Example 45 Initial det~riora~ion rate (kg/mm .sec ) 1.1 4.0 Fiber strength reduction (%) 61 96 Interlaminar sh~ar strength (kg/mm ) 16.9 7O4 Tensile strength in direction perpe~dicular to fiber lkg~mm ) 13.5 6.0 Fatigue limit/
tensile strength 0.32 0.19 ~f~

Example 124 On a pure magnesium foil of 0.5 mm in thickness were unidirectionally arranged a plurality of the in-organic fibers I. Thereon was placed another magnesium foil of same quality and size. The laminate was hot rolled at 670~C to obtain a composite foil of fiber and magnesium. This composite foil was piled up in a total number of 27~ wa~ allowed to stand for 10 minutes at 670C under vacuum, and then was hot pressed at 600C to obtain an inorganic fiber-reinforced magnesium composite materialO
The inorganic fiber was measured for initial deterioration rate (kg~mm2.sec 1) and fiber strength reduction (%~, and the composite material was measured for interlaminar shear strength ~kg/mm2), tensile strength in direction perpendicular to fiber (kg~mm2) and fatigue limit/tensile strength. The Vf of the composite material was 30 % by volume. The results are shown in Table 18.
Comparative Example 46 A carbon fiber-reinforced magnesium composite material was prepared in the same manner as in Example 124 except that the inorganic fiber was replaced by a carbon fiber. The carbon fiber and the composite mate-rial were measured for the above mentioned properties.The results are shown in Table 180 .7 ~ 161 -rrable 18 Comparative 3~xample 12~ Example 46 Initial det~riora~ion rate ~kg/mm .sec ) lol 4~1 Fiber strength reduction (%) 64 96 Interlaminar sh~ar strength ~kg/mm ~ 4.1 1.5 Tensile strength in direction perpe~dicular to Eiber (kgJmm 1 3.1 1.3 Fatigue limit~
tensile strength 0.34 0~21 Example 125 A plurality of the inorganic fibers I were undirectionally arranged on a magnesium alloy foil (specified by JIS A 891) of 0.5 mm in thickness. Thereon was placed another magnesium alloy foil of same quality and size. The laminate was not rolled at 670~C to pre-pare a composite foil of fiber and magnesium alloy. This composite foil was piled up in a total number of 27, was allowed to stand for 10 minutes at 670C under vacuum, and was hot pressed at 6C0C to obtain an inorganic fiber~reinforced magnesium composite material.
The inorganic fiber was measured for initial deterioration rate (kg~mm2.sec 1) and fiber strength reduction (%), and the composite material was measured for interlaminar shear strength (kgJmm2~, tensile strength in direction perpendicular to fiber (kgJmm2) and fatigue limit/tensile strength. The Vf of the composite material was 30 % by volume. The results are shown in Table 19.
Comparative Example 47 A carbon fiber-reinforced magnesium composite r5 ~ 1~2 -material was obtained in the ~ame manner as in Example 125 except that the inorganic fiber was replaced by a carbon f iber . The carbon fiber and the composite mate-rial were ~easured for the above mentioned properties.
The results are shown in Table 19.
Table 19 Comparative xam~le 125 Example 47 Initial det~riora~ion rate (kg/mm ~sec ~ 1.0 4.0 Eiber strength reduction (~ 62 96 Interlaminar sh~ar strength ~kg/mm ) 6.8 2~8 ~ensile strength in direction perpe~dicular to fiber (kg/mm ) 5.2 2.2 Fatigue limit~
tensile strength 0.36 0.27 Example 126 An inorganic fiber~reinforced aluminum com-posite material was prepared in the same manner as inExample 120 except that there was used the inorganic fiber II. The composite material had a Vf of 30 % by volume.
The tensile strength of the composite material was about the same as that of the composite material obtained in Example 120, but the tensile modulus of elasticity was 15.2 t/mm-.
Comparative Example 48 A carbon fiber reinforced aluminum composite material was prepared in the same manner as in Example 120 except that there was used the silicon carbide fiber obtained in ComparatiYe Example 27 (1).

t,~

The tensile strength of the composite material was about the same as that of the composite material obtained in Example 120, but the tensile modulus of elasticity was 6.3 t~mm2O The Vf of the composite material was 30 ~ by volume~
Example 127 (1) 500 g of the same FCC slurry oil as obtained in Reference Example 2 was heated for 1 hour at 450C in a nitrogen gas current of 1 liter/min to distil off the 450C fraction. The residue was filtered at 200C to remove the portion which was not in a molten state at 200C, and thereby to obtain 225 g of a reforming removed pitch~
The reforming pitch had a xylene insoluble content of 75 ~ and was optically isotropic.
(2) 400 9 of the FCC slurry oil was heated at 450C
in a nitrogen gas current to remove the 450C fraction.
The residue was filtered at 200C to remove the portion which was not in a molten state at 200C, and thereby to obtain 180 g of a reforming pitch. 180 g of the re-forming pitch was subjected to a condensation reaction for 7 hours at 400C in a nitrogen current while removing the light fractions formed by the reaction, to obtain 85 g of a heat-treated pitch.
This heat-treated pitch had a melting point of 268C, a xylene insoluble content of 92 % and a quinoline insoluble content of 12 %. The pitch was a mesophase pitch having an optical anisotropy of 89 % when the polished surface was observed by a polarizing microscope~
The pitch is hereinafter referred to as the mesophase pitch (A).
The FCC slurry oil was heated at 420C in a nitrogen gas current to distil off the 420C fraction.
The residue was subjected to a polycondensation reaction for 5 hours at 400C to obtain a mesophase pitch having a melting point of 258C, a xylene insoluble content of ~ 9~

- 16~1 -65 %, a quinoline insoluble content of 6 % and an optical anisotropy oE 52 %. The p1tch is hereinafter referred to as the mesophase pitch (B)o (3) 49 g oE the pitch obtained in (1) above was mixed with 21 g of the organosilicon polyme~ obtained in Reference Example 1 and 20 ml of xylene. The mixture was heated with stirring to distil o$f xylenei and the re-sidue was reacted for 6 hours at 40n~c to obtain 39 g of a precursor reaction product.
Infrared absorption spectrum analysis indicated that in the precursor reaction product there occurred the decrease of the Si-H bond (IR: 2100 cm 1) present in organosilicon polymer and the new formation of Si-C (this C is a carbon of benzene ring) bond (IR~ 1135 cm 1).
Therefore, it became clear that the precursor reaction product contained a structure in which part of the silicon atoms of organosilicon polymer bonded directly with carbons o the polycyclic aromatic ring.
39 g of the precursor reaction product was mixed ~ith 11 g of a xylene solution containing 2.75 g (11 %) of tetraoctoxytitanium ~Ti(OC8H17)~]. The mixture was heated to distil off xylene. The residue was reacted for 2 hours at 340C to obtain 38 g of a reaction pro-duct.
The reaction product contained no xylene in-soluble, had a weight-average molecular weiyht of 1650 and a melting point of 272C~
(4) 35 g of the above reaction product and 70 g of the mesophase pitch (A~ were melt mixed for 1 hour at 310C in a nitrogen atmosphere to obtain a uniform titanium-containing reaction product. The product had a melting point of 272C and a xylene insoluble content of 59 %.
(5) The titanium-containing reaction product was used as a spinning material and subjected to melt spin-ning at 340C using a metallic nozzle of 0.~5 mm in 1~0 ~ J3 ~

diameter. The spun fiber was subjected to curing in air and then to pyrolyzing of 1300C in an argon atmosphere to obtain an inorganic fiber of 10 ~m in diameter.
The inorganic fiber had a tensile strenyth of 320 kg/mm2 and a tensile modulus of elasticity oE 32 t/mm2. The fiber, when the breaking surface was observed by a scanning type electron microscopei had a coral~like random-radial mixed structure consisting of a plurality of piled crystal layers~
The inorganic fiber, when heated (oxidized) in air, showed substantially no weight decrease up to 700C
and showed only 7 % of weight loss at 800~C.
Example 128 39 g of the precursor reaction product obtained in Example 127 t3) was mixed with an ethanol-xylene solution containing 5.4 g (1.5 ~ of tetrakisacetyl-acetonato~irconium. After xylene was distilled off, the residue was polymerized for 1 hour at 250C to obtain 39.5 g of a reaction product.
20 g of the above reaction product and 50 g of the mesophase pitch (A) prepared in the same manner as in Example 127, were mixed in a fine particle state. The mixture was melted in a spinning chimney at 350~C and spun at 340C using a nozzle of 0.2 mm in diameter. The spun fiber was cured at 250~C in air and then pyrolyzed at 1400~C in an argon atmosphere to obtain an inorganic fiber of 11 ~ in diameter.
The fiber had a tensile strength of 325 kg/mm2 and a tensile modulus of elasticity of 35 t/mm2.
Example 129 57 g of a precursor reaction product was ob-tained in the same manner as in Example 127 except that the amounts of the reforming pitch and organosilicon polymer used were changed to 60 g and 40 g, respectively.
40 g of the precursor reaction product was mixed with an ethanol-xylene solution containing 7.2 g (1.5 ~) of hafnium chloride. Af-ter xylene was distilled off, the residue was polymerized for 1 hour at 250~C to obtairl 43~5 g of a reaction product.
20 g of the reaction product and 80 g of the mesophase pitch ~A) were mixed in a fine particle state.
The mix-t-lre was melted and deaerated at 350UC in a spinning chimney, was melt spun at 350C9 was cured at 270C, and was pyrolyzed at 1200C in argon to obtain an inorganic fiber of 12 5 ~. The fiber had a tensile strength of 315 kg/mm and a tensile modulus of elasticity of 35 t/mm2.
Example 130 18 gO of the reaction product obtained in the same manner as in Example 127 (3) and 90 g 3f the meso-phase pitch (B) described in Example 127 (2~ were meltmixed for 1.5 hours at 300C in a nitrogen current to obtain a spinning dope having a melting point of 265C
and a xylene insQluble content of 49 %. The dope was melt spun at 330C using a nozzle of 0.15 mm in diameter, was cured at 3D0C, and was pyrolyzed at 1700C to obtain an inorganic fiber of 8 ~ in diameter. The fiber had a tensile strength of 305 kg/mm and a tensile modulus of elasticity of 38 t/mm .
Example 131 39 9 of the precursor reaction product obtained in Example 127 (3) was mixed with 0.9 g o tetrabutoxy-titanium. The mixture was subjected to the same pro-cedure as in Example 127 to obtain 38.5 g of a reaction product. 18 9 of this reaction product and 90 g of the mesophase pitch (A) described in Example 127 (2) were melt spun at 345C in the same manner as in Example 128, was cured at 300C, and pyrolyzed at 2100C in an argon atmosphere.
The resulting inorganic fiber had a diameter of 7.5 ~(, a tensile strength of 290 kgfmm2 and a tensile modulus of elasticity of 45 t/mm2~

Example 132 An inorganic fiber was obtained i.n the same manner as in Example 131 except that the amount of tetrabutoxytitanium used was 9 0 g and the p~rolyzing temperature was 2500C.
The inorganic fiber had a diameter of 7.5 , a tensile strength of 335 kg/mm and a tensile modulus of elasticity of 55 t/mm .
Example 133 There were uniformly mixed 100 parts of a bisphenol A type epoxy resin (XB2879A manufactured by Ciba Geigy Co.3 and 20 parts of a dicyandiamide curing aqent (XB2879B manufactured by Ciba Geigy Co.). The mixture was dissolved in a 1:1 tby weight) mixed solvent f methyl cellosolve and acetone to prepare a solution containing 28 % of the mixture.
The inorganic fibers obtained in Examples 127-130 were impregnated with the above solution, were unidirectionally taken off using a drum winder, and were heated for 14 minutes at 100C in a heat circulation oven to prepare half-cured inorganic fiber prepregs in which the fibers were arranged unidirectionally. These pre-pregs had a fiber content of 60 % by volume and a thick-ness of 0.2 mm.
Each prepreg was piled up in a total number of 10 and press molded at 11 kg/cm2 at 130C for 90 minutes to obtain four kinds of unidirectionally reinforced epoxy resin composite materials of 250 mm x 250 mm.
A test sample of 12~7 mm (width), 85 mm (length) and 2 mm (thickness) for measurement of flexural strength was prepared from each of the above composite materials, by cutting. Ea~h test sample was subjected to a three-point bending test (span/width = 32, speed ~ 2 mm/min).
The flexural strengths of each composite material at 0 and 90 directions are shown in Table 2G.

- 1~8 --Separately, a composite material was prepared in the same manner as above except that there ~as used a pitch-based carbon fiber havin~ a tensile strength of 280 ky/mm2 and a tensile modulus of elasticity of 55 t/mm2.
The flexural stengths of this composite material are also shown in Table 20.
Table 20 ~lexural strengths (kg/mm2) Fiber 0 90 _ Example 127 203 13~0 Example 123 205 13.2 Example 129 201 13.8 Example 130 198 12.0 Carbon fiber 100 3~5 Example 134 (1) 57 g of the pitch containing 25 ~ of a xylene insoluble portion, obtained in Example 10 tl) was mixed with 25 g of the organosilicon polymer obtained in Refer-ence Example 1 and 20 ml of xylene. The mixture was heated with stirring to distil off xylene, and the re-sidue was reacted for 4 hours at 400C to obtain 57.4 gof a precursor reaction product.
Infrared absorption spectrum analysis indicated that in the precursor reaction product there occurred the decrease of the Si-H bond (IR: 2100 cm 1) present in organosilicon polymer and the new formation of Si-C (this C is a carbon of benzene ring) bond tIR: 1135 cm 1).
Therefore, it became clear that the precursor reaction product contained a polymer having a portion in which part of the silicon atoms of organosilicon polymer bonded directly with carbons of the polycyclic aromatic ring.

57.4 9 or the precursor reaction product was mixed with 15~5 g vf a xylene solution containing 3O87 g (25 ~) of tetraoctoxytitanium ~Ti (OC8H17)4]. AEter xylene was distilled oEf~ ~he r,esidue was reacted for 1 hour at 340C tv obtain 56 g of a reaction product.
The reaction product contained no xylene in-soluble portion/ had a weight-aJerage molecular weight of 1580, a melting point of 258C and a softening point of 2~2C~
~2) 6.4 g of the above reaction product and 90 g of the sarne mesophase pitch as obtained in Example 10 (2) were mixed~ The mixture was melted or 1 hour at 380C
in a nitrogen atmosphere to obtain a uniform titanium-containing reaction product.
The reaction product had a melting point of 264C, a softening point of 307C and a xylene insoluble content of 68 %.
~3) The above reaction product was used as a spin-ning material and melt spun at 360C using a metallic nozzle of 0.15 mm in diameter. The spun fiber was sub-jected to curing at 300C in air and then to pyrolyzing at 1300~C in an argon atmosphere to obtain an inorganic fiber of 7D5 m in diameter.
The fiber had a tensile strength of 358 kg~mm 25 and a tensile modulus of elasticity of 32 t/mm2O The fiber, when the breaking surface was observed by a scan-ning type electron microscope, had a coral-like random-radial mixed structure consisting of a plurality of piled crystal layers.
The inorganic fiber was ground, subjected to alkali fusion, and treated with hydrochloric acid to convert into an aqueous solution. The solution was subjected to high frequency plasma emission sp34tro-chemical analysis (ICP). As a result, the invrganic fiber contained silicon and titanium in amounts of 0.95 %
and 0.06 %, respectively.

The above fiber~ when heated and oxidized in air; showed no reduction in above mentioned mechanical properties evell at 6G0C and W21S superior in oxidation resistance to commercially available carbon fibers which were oxidized and burnt out at 600C~
E`xample 135 39 g of the precursor reaction product obtained in Example 134 was mixed with an ethanol-xylene solution containing 5.4 g (105 %) of tetrakisacetylacetonato-zirconium~ After xylene was distilled off~ the residuewas polymerized at 250C for 1 hour to obtain 39O5 g of a reaction product.
20 g of the reaction product and 50 g of the same mesophase pitch as used in Example 134 (1) were finely ground and melt mixed for 1 hour at 360C. The melt was spun at 350C using a no~zle of 0.2 mm in dia-meter. The spun fiber was cured at 250C in air and then pyrolyzed at 1400C in an argon atmosphere to obtain an inorganic fiber of 11 in diameter.
The fiber had a tensile strength of 345 kg/mm2 and a tensile modulus of elasticity of 35 t/mm2.
Example 136 57 g of a precursor reaction product was ob-tained in the same manner as in Example 134 except that the amounts of the reforming pitch and organosilicon polymer used were changed to 50 g and 40 g~ respectively.
40 g of the precursor reaction product was mixed with an ethanol-xylene solution containing 7.2 g (1.5 %~ of hafnium chloride. After xylene was distilled off, the residue was polymerized for 1 hour at 250C to obtain ~3.5 9 of a reaction product.
20 g of the reaction product and 80 g of the same mesophase pitch as used in Example 134 (2) were finely ground and melt mixed for 1 hour at 350C. The melt was spun at 350C. The spun Eiber was cured at 270C and pyrolyzed at 1200C in argon to obtain an inorgarlic fiber of 12A5 ~ The Eiber had a tensile strength of 335 kg/mm2 and a tensile modulus of elasticity of 35 k/mm Example 13 '7 108 g of the same reaction product as obtained in Example 134 (1) and 90 g of the mesophase pitch ~B) obtained in Example 127 (2) were melt mixed for 1.5 hours at 400~C in a nitrogen current to obtain a spinning dope havillg a melting poin~ of 265C and a ~ylene insoluble 10 COntent O~ 55 %. The dope was melt spun at 350C using a a nozzle of 0.15 mm in diameterO The spun fiber was cured at 300C and then pyrolyzed at 1700C to ohtain an inorganic fiber of 8 ~ in diameter~
The inorganic fiber was ground, subjected to 15 alkali fusion and treated with hydrochloric acid to convert into an aqueous solution~ The aqueous solution was subjected to high frequency plasma emission spectro-chemical analysis (ICP). As a result, the inorganic fiber contained silicon and titanium in amounts of 0.3 and 0.015 ~ ~ respectively.
The fiber had a tensile strength of 335 kg/mm and a tensile modulus of elasticity of 40 t~mm2.
Example 138 39 g of the precursor reaction product obtained 25 in Example 134 was mixed with 0.9 g of tetrabutoxy-titanium, and the procedure of Example 134 (1) was repeated to obtain 38.5 g of a reaction product~
18 9 of this reaction product and 90 g of the same mesophase pitch as obtained in Example 10 (2) were melt spun at 355C in the same manner as in Example 131.
The spun fiber was cured at 300C and then pyrolyzed at 2100C in an argon atmosphere.
The resulting inorganic fiber had a diameter of of 7.5~, a tensile strength of 290 kg/mm2 and a tensile modulus of elasticity of 45 t/mm2.

Example 139 An inorganic fiber was obtained in the same manner as in Example 138 except that the amount of tetrabutoxytitanium used was changed to 9 g and the pyroly~ing temperature was changed to 2500C.
The inorganic fiber had a diameter of 7.5~, a tensile strength of 335 kg/~m2 and a tensile modulus of elasticity of 59 t/mm2.
Example 140 The inorganic fibers obtained in Examples 134-137 were used as a reinforcing agent to obtain uni-directionally reinforced epoxy resin (bisphenol A type3 composite materials (Vf: 60 ~ by volume~. The flexural strengths of these composite materials are shown in Table 21.
Table 21 F ural strengths Ikg/mm ) Inorganic fiber 0 90 Example 134 24813.0 Example 135 24013.2 Example 136 23813.8 Example 137 23512.0 Example 141 (1) 700 g of the FCC slurry oil obtained in Reference Example 2 was heated to 450C in a nitrogen gas current to distil off the 450C fraction. The residue was filtered at 200C to remove the portion which was not in a molten state at 200C, and thereby to obtain 200 g of a reforming pitch.
The reforminy pitch contained a xylene in-soluble portion in an amount of 25 ~ and was optically isctropicO

5~

57 g of the reforming pitch was mixed with 25 y of the organosilicon polymer obtained in ~eference Example 1 and 20 ml of xyleneO The mixture was heated with stirring to distil off xy]ene. The reisdue was reacted for 4 hours at 400C to obtain 57~4 g of a pre-; cursor reacticn product~
Infrared absorption spectrum analysis indicated that in the precursor reaction product there occurred the decrease of the Si-H bond (IR: 2100 cm 1) present in organosilicon polymer and the new formation of Si-C (this C is a carbon of benzene ring) bond (IR: 1135 cm 1) Therefore, it became clear that the precursor reaction product contained a portion in which part of the silicon atoms of organosilicon polymer bonded directly with carbons of the polycyclic aromatic ring.
57.4 g of the precursor reaction product was mixed with 1505 g of a xylene solution containing 3.87 g (25 ~ of tetraoctoxytitanium [Ti5OC8H17)4]. After xylene was dis~illed off, the residue was reacted for l hour at 340C to obtain 56 g of a reaction product.
The reaction product contained no xylene in-soluble portion and had a weight-average molecular weight of 1580, a melting point of 258C and a softening point of 292C.
180 g of the above reforming pitch was sub-jected to a polycondensation reaction for 8 hours at 400C while removing the light fractions generated by the reaction, to obtain 97.2 g of a heat-treated pitch.
The heat-treated pitch had a melting point of 263C, a softening point of 308C, a xylene insoluble content of 77 % and a quinoline insoluble content of 31 %. The pitch, when the polished surface was observed by a polarizing microscope, was a mesophase pitch having an optical anisotropy of 75 %.
6.4 g of the reaction product and 90 % of the mesophase pitch were melt mixed for l hour at 380C in a - 17~ -nitrogen atmosphere to obtain a uniform ti~anium-contain-lng reaction product.
The reaction product had a melting point of 264C, a softening point of 307"C and a xylene insoluble content of 68 %~
The reaction product was used as a spinning material and melt spun at 360C using a metallic nozzle of 0.15 mm in diameter. The spun fiber was cured at 300C in air and then pyrolyzed at 1300C in an argon atmosphere to obtain an inorganic fiber IV of 7.5 ~ in diameter.
The inorganic fiber had a tensile strength of 358 kg/mm2 and a tensile modulus of elasticity of 32 t/mm . The fiber, when the breaking surface was observed by a scanning type electron microscope, had a coral-like random-radial mixed structure consisting of a plurality of piled crystal layersO
The inorganic fiber was ground, subjected to alkali fusion, treated with hydrochloric acid, and con-2~ verted to an aqueous solution. The aqueous solution wassubjected to high frequency plasma emission spectro~
chemical analysis (ICP). As a result, the inorganic fiber contained silicon and titanium in amounts of 0.95 and 0.06 %, respectively.
(2) 100 parts of a bisphenol A type epoxy resin (XB2879A manufactured by Ciba Geigy Co.) and 20 parts of a dicyandiamide curing agent (XB2879B manufactured by Ciba Geigy Co.) were mixed uniformly. The mixture was dissolved in a 1~1 (by weight~ mixed solvent of methyl cellosolve and acetone to obtain a solution containing 28 % of the mixture.
The inorganic fiber IV obtained in (1) above was impregnated with the above solution, was taken off unidirectionally using a drum winder, and was heated for 14 minutes at 100C in a heat circulation oven to prepare a half-cured inorganic fiber prepreg wherein the fiber had - ~75 -been arranged unidirectionally~ The prepreg had a Eiber content of 60 ~ by volume and a thickness of O.lS mm.
The prepreg was piled up in a total number of 10 with the fibers of all the prepregs arrangecl in the same direction and press molded at 7 kg/cm2 for 4 hours at 17UC to obtain a unidirectionally reinforced epoxy resin composte material of 250 mm x 2$0 mm.
From the composite material was cut out a test sample of 12.7 mm (width), 85 mm (length) and 2 mm (thickness) for flexural strength measurement. Using the test sample~ a three-point bending test (span/width = 32 mm) was effected at a speed of 2 mm/min. The mechanical properties of the composite material are shown below.
Tensile strength tkg/mm2)192 Tensile modulus ~f elasticity (t/mm ) 19 Flexural strenqth ~kg~mm ) 152 Flexural modulus of elasticity (t/mm2) 18 Tensile strength in direction2 perpendicular to fiber (kg/mm ) 6.9 Tensile modulus of elasticity in direction p~rpendicular to fiber tt/mm ~ 5.5 Flexural strength in directio~
perpendicular to fiber (kg/mm ) lQ.2 Flexural modulus of elasticity in direction p~rpendicular to fiber (t/mm ) 5.4 Interl~minar shear strength (kg/mm ~ 9.3 Flexural shock (kg.cm/mm2) 272 ,5~

Example 142 (1) 39 g of the same precursor reaction product as used in Example 141 (1~ was mixed with an ethanol-xylene solution containing 5 4 g ~1.5 %) of tetrakisacetyl-acetonatozirconium. After xylene and ethanol were dis-tilled off~ the residue was polymerized Eor 1 hour at 250C to obtain 39.5 y of a reaction product.
2G g of the reaction product and 50 g of the same mesophase pitch as used in Example 141 (1) were finely ground and then melt mixed for 1 hour at 360~C~
The mixture was melt spun at 350C using a nozzle of 0.2 mm in diameter. The spun fiber was cured at 250C in air and then pyrolyzed at 1400C in an argon atmosphere to obtain a zirconium-containing inorganic fiber V of 11 5 in diameter.
The inorganic fiber had a tensile strength of 345 kg/mm2 and a tensile modulus of elasticity of 35 t/mm2 .
(2) There was used, as a reinforcing fiber, the inorganic fiber V obtained in (1) above; as a matrix, there was used a commercially available unsaturated polyester resin in place of the epoxy resin; and the procedure of Example 141 was repeated to prepare an inorganic fiber-reinforced polyester composite material having a fiber content of 60 % by volume. The mechanical properties of the composite material are shown below.
Tensile strength (kg/mm2)180 Tensile modulus 2f elasticity (t/mm ) 19 Flexural strength (kg/mm2) 240 Flexural modulus2of elasticity ~t~mm ) 18 Tensile strength in direction perpendicular to fiber (kg/mm2) 6.5 Tensile ~odulus of elasticity in direction p~rpendicular to fiber (t/mm ) 5.5 Flexural strength in directio~
perpendicular to Eiber (kg/~m ~ 9.7 Flexural modulus of e:Lasticity in direction p~rpendicular to fiber (t/mm ) 5.5 Interl~minar shear strength (kg/mm ) 9.0 Flexural shock (kg.cm/mm2) 264 Example 143 Sl) 57 g of a precursor reaction product was ob-tained in the same manner as in Example 141 ~1) except that the amounts of the reformin~ pitch and organosilicon polymer used were changed to 60 g and 40 g, respectively.
40 g of the precursor reaction product was mixed with an ethanol-xylene solution containing 7.2 g (1.5 %) of hafnium chloride. After xylene and ethanol were distilled off, the residue was polymeriæed for 1 hour at 250C to obtain 43.5 g of a reaction product.
20 g of the reaction product and 80 9 of the same mesophase pitch as used in Example 141 (1) were finely ground and then melt mixed for 1 hour at 360C.
15 The mixture was melt spun at 350C using a nozzle of 0~2 mm in diameter. The spun fiber was cured at 270C in air and pyrolyzed at 1200C in an argon atmosphere to obtain a hafnium-containing inorganic fiber VI of 12.5 ~ in diameter.
The inorganic fiber had a tensile strength of 335 kg~mm2 and a tensile modulus of elasticity of 35 t~mm2 .
(2) The procedure of Example 141 was repeated except that there was used, as a reinforcing fiber, the inorganic fiber VI obtained in (1) above and, as a matrix~ there was used a polyimide resin manufactured by - 17~
Ube Industries, Ltd. in place of ~he epoxy resin, to prepare an inorganic fiber-reinforced polyimide composite material having a fiber content: of 60 % by volume.
The mechanical properties of the composite material are shown below.
Tensile strength (kg~'mm2) 177 Tensile modulus ~f elasticity ~t/mm ~ 19 Flexural strength (kg/mm ) 239 Flexural modulus of elasticity lt/mm21 18u5 Tensile strength in direction2 perpendicular to fiber ~kg/~n ) 6~4 Tensile modulus of elasticity in direction p~rpendicular to fiber tt/mm ) 5.4 Flexural strength in directio~
perpendicular to fiber (kg/mm ) 9.6 Flexural modulus of elasticity in direction p~rpendicular to fiber (t/mm ) 5~4 Interl~minar shear strength (kg/mm ) 8.9 Flexural shock (kg.cm/mm2) 261 Example ~44 ~1) 1.8 g of the same reaction product as obtained in Example 141 (1) and 90 9 of a mesophase pitch were melt mixed for 1.5 hours at 400C in a nitrogen current to obtain a spinning dope having a melting point of 265C
and a xylene insoluble content of 55 %. The dope was melt spun at 350~C using a a nozzle of 0.15 mm in dia-meter. The spun fiber was cured at 300C and then 1~ pyrolyzed at 1700~C to obtain an inorganic fiber VII of 8~ in diameter.

The inorgallic fiber VII ~as ground, subjected to alkali fusionO treated with hydrochloric acid, and converted to an aqueous solutiomO The aqueous solution was subjected to high frequency plasma emission spectro-chemical analysis (ICP)o ~s a :result, the inorganicfiber VII contained silicon and titanium in amounts of 0O3 % and 0.015 %, respectively.
The fiber had a tensile strength of 335 ky/mm and a tensile modulus of elasticity of 40 timm2.
(2) The inorganic fiber VII obtained in (1) above was used as an inorganic fiber and the procedure of Example 141 was repeatd to obtain an inorganic fiber-reinforced epoxy composite material having a fiber con-tent of 60 % by volume.
The mechanical properties of the composite material are shown below.
Tensile strength (kg/mm )180 Tensile modulus ~f elasticity (t/mm ) 24 Flexural strength (kg/mm2) 242 Flexural modulus of elasticity (t/mm2~ 22 Tensile strength in direction2 perpendicular to fiber (kg/mm ) 6.5 Tensile modulus of elasticity in direction p~rpendicular to fiber (t/mm ) 6.6 Flexural strength in directio~
perpendicular to fiber (kg/mm ) 9O9 Flexural modulus of elasticity in direction p~rpendicular to fiber (t/mm ) 6.4 Interl~minar shear strength ~kg/mm ) 9.0 Flexural shock (kg.cm/mm2) 265 .~0~

Example 145 100 parts of a bisphenol A type epoxy resin (xs2879A manufactllred by Ciba Geigy Co.1 and 20 parts of a dicyandlamide curing agent (XB287gB manufactured by Ciba Geigy Co.) were mixed uniformly. The mixture was dissolved in a 1:1 (by weight) mixed solvent of methyl cellosolve and acetone to prepa e a solution containing 28 ~ of the mixture~
The same inorganic fiber IV as used in Example 141 (1) were impregnated with the above solution, was taken off unidirectionally using a drum winder, and was heated for 14 minutes at ]00C in a heat circulation oven to prepare half-cured inorganic fiber prepreg wherein the fiber had been arranged in the same direction.
~sing a surface-treated carbon fiber ~poly-acrylonitrile-based, tensile strength = 300 kg/mm2, tensile modulus of elasticity = 24 t/mm2, fiber diameter = 7~ ) and~ in the same manner as above, there was pre-pared a half-cured carbon fiber prepreg sheet wherein the fiber had been arranged in the same direction.
The inorganic IV fiber prepreg sheet and the carbon fiber prepreg sheet both obtained above were piled up by turns with the fibers directed in the same direc-tion and then hot pressed to prepare a hybrid fiber (inorganic fiber/carbon fiber)-reinforced epoxy composite material.
The composite material had a total fiber con-tent of 60 % by volume (inorganic fiber = 30 % by volume~
carbon fiber = 30 ~ by volume)O
The composite material had a tensile strength at 0 of 197 kg/mm2, a tensile modulus of elastieity at 0 of 16.8 t/mm2, a flexural strength at 0~ of 199 kg/mm2, a flexural strength at 90 of 8.0 kg/mm2, an interlaminar shear strength of 9.1 kg/mm2 and a flexural shock of 235 kg.cm/cm2.

-~&15 Example 146 A hybrid fiber-reinforced epoxy composite material was peepared in the same manner as in Example 145 except that the carbon fiber was replaced by the same Si-Ti-C-O fiber as obtained in Example 91 (1)~ The composite material had a total fiber content of 60 % by volume tinorganic fiber = 30 ~ by volumei Si-Ti-C-O fiber = 30 % by volume). The composite material had a tensile strength at 0~ of 207 kg/mm2, a tensile modulus of elasticity at 0 of 15~9 t/mm~, a flexural strength at 0 of 221 kg/mm2, a flexural strength at 90 of 13.1 kg/mm2, an interlaminar shear strength of 2.9 kg/mm2 and a flexural shock of 290 kg.cm/cm .
Examples 147-149 Hybrid fiber-reinforced epoxy resin composite materials were prepared in the same manner as in Example 145 except that the carbon fiber was replaced by an alumina fiber, a silicon carbide fiber or a glass fiber each having the properties shown in Table 7 given pre-viously (these fibers are referred to as second fiber for reinforcement). These composite materials had a total fiber content of 60 % by volume (inorganic fiber = 30 %
by volume, second fiber for reinforcement = 30 % by volume) .
The properties of the above hybrid fiber-rein-forced epoxy resin composite materials are shown in Table 22.

- 1~2 -Table 22 , . , \ ~ ~ample 147 EX ~ le 1~8 ~ample 149 \ Second fiber ~ _ _ _ _ \ for rei~orcement .~umina S.ilicon E-glass \ fiber carbide f iber M~hanical properti ~ \ -Eiber . . _ .
Tensile stre~th ~kgJmm ) 166 198 162 __ _ __ ._ Tensile modulus ~f elasticit~ (t/mm) 16 15 11 _ _ . _ Flexural stre~th tkg/mm2) 192 218 181 Flexural m~lus2of elasticity ~tJmm ) 14 13 11 .
Compression strength ~kg/mm2l 190 196 169 Example 150 As an inorganic fiber, there was used the lnorganic fiber V obtained in Example 142 ~1); there was used, in place of the carbon fiber~ a silicon carbide riber using carbon as a core and having a diameter of 140 ~, a tensile strength of 350 kg~mm2 and a tensile modulus of elasticity of 43 t/mm2; and the procedure of Example 142 was repeated to obtain a hybrid fiber-rein-forced epoxy resin composite material. The composite material had a total f.iber content of 46 % by volume (inorganic fiber = 30 % by volume, silicon carbide fiber using carbon as a core = 16 ~ by volume). The composite material had a tensile strength at 0 of 171 kg/mm2~ a tensile modulus of elasticity at 0 of 22 t/mm2~ a flexural strenqth at 0 of 218 kg/mm2 and a flexural strength at 90 of 6.9 kgJmm2 ~ 1~3 -Example 151 There was used~ as an inorganic fiber, the inorganic fiber VI obtained in Example 143 ~1); there was used~ in place of the carbon fiber, a boron fiber having a dîameter of 140 ~, a tensile strength f 357 kg/mm2 and tensile modulus of elasticity oE 41 t/mm ; and the pro-cedure of Example 145 was repeated to prepare a hybrid fiber-reinforcecl epoxy resin composite materlal. The composite material had a total fiber content of 50 ~ by volume ~inorganic fiber = 30 ~ by volume, boron fiber =
20 % by volume~
The composite material had a tensile strength at 0 oE 185 kg/mm2, a tensile modulus of elasticity at 0 of 21 t/mm~, a flexural strength at 0 oE 219 kg/mm and a flexural strength at 90 of 7.8 kg/mm2 Example 152 There was used, as an inorganic fiber~ the inorganic fiber VII obtained in Example 144 (1); there was used, in place of the carbon fiber, an aramid fiber having a tensile strength of 270 kg/mm2 and a tensile modulus of elasticity of 13 t/mm2; and the same procedure as in Example 145 was repeated to prepare a hybrid fiber-reinforced epoxy resin composite material. The composite material had a total fiber content of 50 % by volume (inorganic fiber = 30 ~ by volume, aramid fiber = 30 % by volume).
The composite material had a tensile strength, a tensile modulus of elasticity and a flexural strength all at 0 of 162 kg/mm2, 16 t~mm2 and 166 kg/mm2, respectively, and was significantly superior in strengths and modulus of elasticity as compared with an aramid fiber-reinforced epoxy resin (the aramid fiber-reinforced epoxy resin having a fiber content of 60 ~ by volume had a tensile strength, a tensile modulus of elasticity and a flexural strength all at 0 of 95 kg/mm2, 5.3 t/mm2 and 93 kg/mm , respectively). The composite material had a J

flexural ~hock of 276 kg~cm/cm2, which was not signifi-cantl~ lower than the high shock resistance of aramid f.ibers (the aramid fiber-reinforced epoxy resin having a fiber content of 60 ~ by volume had a Elexural shock of 302 kg.cm/cm2).
Example 153 To a ~-silicon carbide powder having an average particle diameter of 0.2~m were added 3 % of a boron carbide powder and 10 ~ of a polytitanocarbosilane powder, and they were mixed thoroughlyO The resulting mixture and a plurality of the inorganic fibers obtained in Example 127 (53, each having a length of 50 mm and arranged in the same direction~ were piled up by turns so that the inorganic fiber content besame 40 ~ by volume.
The laminate was press molded in a mold at 500 kg~cm2.
The molded material was heated to l950~C in an argon atmosphere at a rate of 200C/h and kept at that tem-perature for 1 hour to obtain an inorganic fiber-rein-forced silicn carbide composite sintered material, EXample 154 An inorganic fiber-rein.forced silicon carbide composite sintered material was obtained in the same manner as in Example 153 except that there was used, as a reinforcing fiber, the inorganic fiber obtained in Example 132-The mechanical strengths of the sintered materials obtained in Examples 153 and 154 are shown in Table 23. The flexural strength in Table 23 is a value obtained in a direction normal to fiber. In Table 23, there are also shown the values of Comparative Examples 27, 28 and 28 ~see Table 10).

3~
- 1~6 --Example 155 To an ~-silicon nitride powder having an average particle diameter of 0,5 m s~ere added 2 % of alumina, 3 % of yttria and 3 % of aluminum nitride~ and they were mixed thoroughly. The resulting mixed powder and a plurality of the inorganic fibers obtained in Example 128, having a length of 50 mm and arranged in the same direction were piled up by turns so that the fiber content became about 10 ~ by volume. At ~his time, the fiber direction of one inorganic fiber layer was dif-ferent from that of the lower inorganic fiber layer by 90. The resulting laminate was kept at 300 kg/cm2 at 1750C for 30 minutes in a hot pressing machine to obtain an inorganic fiber-reinforced silicon nitride compvsite sintered material.
The properties (flexural strength at room temperature and 1400C, etc.) of the sintered material are shown in Table 24.
Table 24 Flexural K Flexural Deterioration streng~h rac~iO stre~th rate 2 -1 (kg~mm ) reduction (kg/mm .sec ) (%) (1200C) (1750C) Rtoomp. 1400C
_ _ ~ample 155 128 80 2.2 0 16 Comparative xample 30 120 45 _ 55 Example 156 In isopropanol were thoroughly dispersed (a) a borosilicate glass (7740) powder (a product of Corning Glass Works) having an average partiole diameter of 44 m 3~

and (h) 45 ~ by volume of chopped fibers obtained by cutting the inorganic fiber obtained in Example 129 into a length of 10 mm. The resulting slurry and a plurality of the same inorganic fibers arranged in the same direc-tion were piled up by turns~ The laminate was dried andthen treated by a hot pressing machine at 750 kg/mm2 at 1300C for about 10 minutes in an argon atmosphere to obtain an inorganic fiber-reinforced glass composite material~

Table 25 Flexural K Flexural Deterioration streng~h r~io strer,gth rate ~ -1 (kg/mm ~ reduction ~kg/mm .sec ) r ~ ~%) (S00C)(1300~C) ~ample 156 21.0 5.1 2 0.25 .
Comparative ~a~ple 31 14.2 4 1.50 In Table 25, the values of Comparative Example 31 also shown (see Table 12).
Example 157 An alumina powder having an average particle diameter of 0.5~ m was mixed with 2 % of titanium oxide.
To the resulting mixture was added a spun fiber of a titanium-containing reaction product lsaid spun ~iber is a precursor for the inorganic fiber obtained in Example 127 (5)~ so that the fiber content in final mixture became 15 % by volume. The mixture was stirred thorough-ly in an alumina ball mill. The average length of the precursor fiber was about 0.5 mm~ The resulting mixture was sintered at 2000~C in an argon atmosphere by a hot pressing machine. The resulting sintered material was subjected to a spalling test. That is, a plate (40 x 10 ~dP O q;~ ! 5 ~1 - 1~8 -x 3 mm) prepared from the sintered material was rapidly heated for 20 minutes in a nitrogen atmosphere in an oven of 1300C~ taken out, and forcibly air-cooled for 20 minutes; this cycle was repeated; thereby, there was examined a cycle number at which cracks appeared in the plate for the first time.
The oycle number and mechanical strengths of tbe sintered material are shown in Table 26.
Table 26 _ _ _ Flexural Spalling r~tio strength test reduction ~%~ (~00C) _ Example 157 3.1 5 9 Comparative Example 32 _ _ In Table 26, the values of Comparative Example 32 are also shown (see Table 13).
Example 158 A ~-silicon carbide powder having an average paricle diameter of 0.2~ m was thoroughly mixed with 3 ~
of a boron carbide powder and 10 ~ of a polytitanocarbo-silane powder. The mixture and a plurality of the in-organic fibers (obtained in Example 134) having a length of 50 mm and arranged in the same direction were piled up by turns so that the fiber content became 40 ~ by volume.
The laminate was press molded at 500 kg/mm2 in a mold.
The resulting molded material was heated to 1950C at a rate of 200C/h in an argon atmosphere and kept at that temperature for 1 hour to obtain an inorganic fiber-reinforced silicon carbide composite sintered material.

Example 159 (1~ 1.8 g of the reaction product of Example 134 (1~ and 9Q g of the same mesophase pitch as obtained in Example 10 (2) were melt mixed for 1~5 hours at 400~C in a nitrogen current to obtain a spinning material having a melting point of 265~C ancl a xylene insoluble cor.tent of 55 %.
The material was melt spun at 350C using a a nozzle of 0.15 mm in diameter. The spun fiber was cured at 300~C and then pyrolyzed at 2500~C to obtain an inorganic fiber of 7 ~ in diameter.
ICP analysis conducted in the same manner as in Example 134, indicated that the inorganic fiber con-tained silicon and titanium in amounts o~ 0.3 ~ and 1~ 0.015 %, respectively. The fiber had a tensile strength of 345 kg/mm2 and a tensile modulus of elasticity of 60 t~mm~.
(2) The same procedure as in Example 158 was re-peated except that there was used, as a reinforcing fiber, the inorganic fiber obtained in (1) above, to obtain an inorganic fiber-reinforced silicon carbide composite sintered material.
The mechanical strengths of the sintered materials obtained in Examples 158 and 159 are shown in Table 27. In Table 27, flexural strength is a value obtained in a direction normal to fiber.

Example 160 An ~ silicon nitride ]powder having an average particle diameter of 0.5~ m was thoroughly mixed with 2 %
nf alumina, 3 % of yttria and 3 ~ of aluminum nitride.
The resulting powder and a plurality of the inorganic fibers of Example 135 having a length of 50 mm and ar-ranged in the same direction were piled up by turns so that the fiber content became about 10 % by volume. At this time, the fiber direction of one inorganic Eiber layer was different from that of the lower inorganic 2 fiber layer by 90. The laminate was kept at 300 kg/cm at 1750C for 30 minutes in a hot pressing machine to obtain an inorganic fiber-reinforced silicon nitride composite sintered material.
The flexural strength at room temperature and 14000C, etc. of the sintered material are shown in Table 28~
Table ~8 _ Flexural Kl Flexur~ Deterioration streng~h ractiO strength rate (kg/mm) reduction (kg~mm2 seC-l~
t%) ~1200C) (1750C) Rtemp. 1400C
_ _ Example 160 130 82 2.2 0.16 Example 161 In isopropanol were thoroughly dispersed (a) a borosilicate glass t7740) powder (a product of Corning Glass Works) having an average particle diameter of 44~m and (b) 45 % by volume of chopped fibers obtained by cutting the inorganic fiber of Example 136 into a length of 10 mm. The resulting slurry and a plurality of the same inorganic fibers arranged in the same direction were piled up by turns~ The laminatle was dried and then treated by a hot pressing machine at 750 kg/mm2 at 1300C
for about 10 minutes in an argon atmosphere to obtain an inorganic fiber-reinforced glass composite material.
The results are shown in Table 290 Table 29 _ Fl~xural K Flexural Deterioration stre~ ~ r~io strength rate 2 -1 tkgtmm ) reduction tkg~m~ .sec (r~ (~) (9OODC) (1300C) temp.) ~ample 161 23.U 5.1 0.25 Example 162 A plain weave fabric of the inorganic fiber obtained in Example 127 (5) was immersed in a methanol solution of a resole type phenolic resin (MRW-3000 manu-factured by Meiwa Kasei) and then pulled up. The im-pregnated fabric, after methanol was removed, was dried ~o obtain a prepreg sheet. From the prepreg sheet were cut out square sheets of 5 cm x 5 cm. The square sheets were piled up in a mold and pressed at 50 kg/cm at 200C to cure the phenolic resin to obtain a molded material. The molded material was buried in a carbon powder and heated to 1000C at a rate of 5C/h in a nitrogen current to obtain an inorganic fiber-reinforced carbon composite material. The composite material was a porous material having a bulk density of 1.26 g~cm3.
The compposite material was mixed with a powder of the mesophase pitch (A) [this pitch is an inter-mediate of the inorganic fiber of Example 127 t5)]. Themixture was placed in an autoclave and heated to 350C in a nitrogen atmosphere to melt the pitch and then the autoclave inside was made vacuum to impregnate the pores i~ r~

oE the composite material with the molten mesophase pitch~ Thereafter, a pre~sure of 100 kg/cm2 was applied for further impregnation. The impregnated composite material was heated to 300C at a rate of 5C/h in air for curing and then was carboniæed at 1300C. The above impregnation with mesophase pitch ancl carbonization were repeated three more times to obtain a composite material having a bulk density of 1086 gJcm and a 1exural strength of 39 Icg/mm~O
Using the inorganic fibers obtained in Examples 128 and 129 and in the same manner as above~ there were prepared composite materials. The composite material prepared using the inorganic fiber of Example 128 had a bulk density of 1.86 g/cm3 and a flexural strength of 40 kg/mm2, and the composite material prepared ~sing the inorganic fiber of Example 129 had a bulk density of 1.85 g/cm3 and a flexural strength of 37 kg/mm2. These com-posite materials had a fiber content (Vf) of 60 ~ by volume. (The Vf in the following Example 163 was also 60 % by volume.) Example 163 A graphite powder having an average particle diameter of 0.2 m and a powder of the mesophase pitch (A) [the pitch is an intermediate of the inorganic fiber f Example 127 tS)] were ground and mixed at a 1:1 weight ratio. The resulting powder and a fabric of the in-organic fiber of Example 131 were piled up by turns. The laminate was hot pressed at 100 kg/cm2 at 350C to obtain a molded material. The molded material was subjected to four times of the same impregnation with mesophase pitch and carbonization as in Example 162~ to obtian a composite material having a bulk density of 1.92 g~cm3 and a flexural strength of 42 kgimm2. When the composite material was heated to 2500C in an argon atmosphere to graphitize the matrix, the flexural strength improved to 50 kg/mm2.

D~
- 19~1 -Example 16~
A plain wea~e fabric of the inorganic fiber obtained in Example 134 was immersed in a methanol solution of a resole type phenolic resin (MRW-3000 manu-factured by Meiwa Kasei) and then pulled up. The im--pregnatecl fabric, after methanol was removed, was dried to obtain a prepreg sheet~ From the prepreg sheet were cut out square sheets of 5 cm x 5 cm. The square sheets were piled up in a mold and pressed at 50 kg~m2 at 200C
to cure the phenolic resin to obtain a molded material.
The molded material was buried in a carbon powder and heated to 1000C at a rate of 5C/h in a nitrogen current to obtain an inorganic fiber-reinforced carbon composite material. The composite material was a porous material lS having a bulk density of 1~25 g/cm3.
The compposite material was mixed with a powder of the mesophase pitch which is an intermediate oE the inorganic fiber of Example 134. The mixture was placed in an autoclave and heated to 350C in a nitrogen atmos-phere to melt the pitch and then the autoclave insidewas made vacuum to impregnate the pores the composite material with the molten mesophase pitch. Thereafter, a pressure of 100 kg/cm~ was applied for further im-pregnation. The impregnated composite material was heated to 300C at a rate of 5C/h in air for curing and then was carbonized at 1300C. The above impregnation with mesophase pitch and carbonization were repeated three more times to obtain a composite material having a bulk density of 1.87 g~cm and a flexural strength of 44 kg/mm2.
Using the inorganic fibers obtained in Examples 135 and 136 and in the same manner as above, there were prepared composite materials. The composite material prepared using the inorganic fiber of Example 135 had a bulk density of 1.86 g/cm and a flexural strength of 45 kg/mm2, and the composite material prepared using the 5i8 inorganic fiber oE Example 136 had a bulk density of 1.85 gtcm3 and a flexural strength oE 39 kg/mm2. These com-posite materials had a fiber content (Vf) of 60 % by volume. ~The Vf in the following Example 1~5 was also 60 ~ by volume~) Example 165 A graphite powder having an averaqe particle diameter of 0.2 ~m and a powder of the mesophase pitch (A) which is an intermediate of the inorganic fiber of Example 134 were ground and mixed at a 1:1 weight ratio~
The resulting powder and a fabric of the inorganic fiber of Example 159 ~1) were piled up by turns. The laminate was hot pressed at 100 kg/cm2 at 350C to obtain a molded material. The molded material was subjected to four times of the same impregnation with mesophase pitch and carbonization as in Example 164, to obtian a composite material having a bulk density of 1.92 g/cm3 and a flexural strength of 47 kg/mm2. When the composite material was heated to 2500C in an argon atmosphere to graphitize the matrix, the flexural strength improved to 55 kg/mm2.
Example 166 (1) The procedure of Example 134 was repeated except that the reaction product of Example 134 (1) (melting point = 258C, softening point = 292C) and the mesophase pitch of Example 134 (2) were used as a ratio of 1:1, to obtain a titanium-containing reaction product.
(2) A two-dimensional plain weave fabric of the inorganic fiber obtair.ed in Example 134 was cut into discs of 7 cm in diameter. The discs were impregnated with a xylene slurry containing 30 ~ of the spinning material polymer used in Example 134 and then were dried to obtain prepreg sheets. These prepreg sheets were piled up in a mold in a total sheet number of 30, with a fine powder of the titanium-containing reaction product of (1) above being packed between each two neighbouring 0~3~ ~3 prepreg sheets and with the fiber direction of one pre-preg sheet being advanced by 45 from that of the lower prepreg sheetO The laminate was hot pressed at 50 kg/cm2 at 350C to obtain a disc-like ~olded materialO The molded material was buried in a carbon powder bed for shape retention, was heated to 800C at a cate of 5C/h in a nitrogen current, and was further heated to 1300C
to carbonize the matrixD The resulting composite material had a bulk density of 1.20 gJcm3.
The composite material was immersed in a xylene slurry containing 50 % of the metal-containing reaction product of (1) above. The resulting material was heated to 350C under vacuum while distillng oEf xylene; a pre~sure of 100 kg/cm2 was applied for impregnation;
then, the material was heated to 300C at a rate of 5C/h in air for curing and thereafter carbonized at 1300C.
This impregnation and carbonization treatment was re-peated three more times to obtain a composite material having a bulk density of 1.95 g/cm3. The composite material had a flexural strength of 59 kg/n~2.
Example 167 There were mixed ~a) 50 parts of an inorganic substance obtained by prefiring the spinning polymer used in Example 159 ~1), at 1300C in nitrogen and (b) 50 parts of a powder of the titanium-containing reaction product of Example 166 (1). The resulting mixture and a two-dimensional plain weave fabric of the inorganic fiber obtained in Example 159 (1) were piled up by turns. The laminate was hot pressed at 100 kg/cm2 at 400C to obtain a molded material. The molded material was carbonized in the same manner as in Example 166. The resulting mate-rial was subjected to four times of (a) the impregnation with the titanium-containing reaction product of Example 166 (1) and (b) carbonization, in the same manner as in Example 166. The resulting composite material had a bulk density of 2.02 gJcm3 and a flexural strength of 3~8 - ~97 ~
61 ky/mm~0 When the composite material was pyrolyzed at 2200C in argon, the bulk density and flexural strength improvecl to 2005 g/cm3 and 65 kl3/mm~, respectiYelyO
Example 168 (l~ The procedure of Example 135 was repeated except that the reaction product which is an intermediate of the inorganic fiber of Example 135 and the mesophase pitch were used at a 1:1 ratio, to obtain a zirconium-containing reaction product.
(2) The procedure o Example 166 was repeated except that as a reinforcing fiber there was used the inorganic fiber of Example 135~ there was usedt as a polymer for prepreg sheet preparation, the spinning polymer used in Example 135, and as a packing powder used in molding there was used the zirconium~containing re-action product of (1) above, whereby a composite material having a bulk density of 1.21 gtcm3 was obtained~
The composite material was subjected to the impregnation with the zirconium-containing reaction product of (1) above in the same manner as in Example 166, to obtain a composite material haYing a bulk density of 1.97 g/cm3 and a flexural strength of 61 kg/mm2.
Example 169 tl) The procedure of Example 136 was repeated except that the reaction product which is an intermediate of the inorganic fiber of Example 136 and the mesophase pitch were used at a 1:1 ratio, to obtain a hafnium-containing reaction product.
(2~ The procedure of Example 166 was repeated except that as a reinforcing fiber there was used the inorganic fiber of Example 1369 there was used, as a polymer for prepreg sheet preparation, the spinning polymer used in Example 136, and as a packing powder used in molding there was used the metal-containing reaction product of (1) above, whereby a composite material having a bulk density of 1.25 g~crn3 was obtained.

- 19~ -The composite material was subjected to the impregnation with the hafnium-c~ntaining reaction product of (1) above in the same manner as in Example 156, to obtain a composite material having a bulk density of 2O05 g/cm3 and a flexural strength of 56 kg/mm2.
Example 170 The composite materlals of Examples 166, 167.
168 and 169 were heated for 1 hour in an oven containing air of 600C and then measured Eor flexural strength.
There was seen no strength reduction in any composite material (see Comparative Examples 33 and 34).
Example 171 (lj 6.4 g of the precursor reaction product used in preparation of the inorganic fiber of Example 134 and 90 g f a mesophase pitch were melt mixed for 1 hour at 380C in a nitrogen atmosphere to prepare a reaction product.
(2) S0 g of the organic polymer used in preparation of the inorganic fiber of Example 134 and 5Q g of a reforming pitch were treated in the same manner as in Example 134 to obtain a precursor reaction product. This precursor reaction product and the mesophase pitch of Example 134 were melt mixed at a 1:1 ratio for 1 hour at 380~C in a nitrogen atmosphere to obtain a reaction product~
(3) A two-dimensional plain weave fabric oE the inorgnaic fiber obtained in Example 13~ was cut into discs of 7 cm in diameter. The discs were immersed in a xylene slurry containing 30 % of the reaction product of (1) above and then were dried to obtain prepreg sheets.
These prepreg sheets were piled up in a mold in a total sheet number of 30, with a fine powder of the reaction product of ~2) above being packed between each two nei-bouring prepreg sheets and with the fiber direction of one prepreg sheet being advanced by 45 from that of the lower prepreg sheet. The laminate was hot pressed at 2 - 199 _ 50 kg/cm at 350C to obtain a disc-like molded material.
The molded material was buried in a carbon powder bed for shape retentiorl, was heated to 800C at a rate of 5~C/h in a nitrogen current~ and was further heated to 1300C to carbonize the matrix. The resulting composite material had a bulk density of 1.21 g/cm ~
The composite material was immersed in a xylene slurry containing 50 % of the reaction product of (2) above. The resulting material was heated to 350C under 1~ vacuum while distilling off xylene~ a pressure cf 100 kg/cm2 was applied for impregnation; then, the material was heated to 300C at a rate of 5C/h in air for curing and thereafter carbonized at 1300C. This impregnation and carbonization treatment was repeated three more tirnes to obtain a composite material having a bulk density o 1.93 9/cm3. The composite material had a flexural strength of 57 kg/mm2.
Example 172 There were mixed (a~ 50 parts of an inorganic substance obtained by prefiring the reaction product of Example 171 (1) at 1300C in nitogen and (b) 50 parts of a powder of said reaction product. The resulting mixture and a two-dimensional plain weave fabric of the inorganic fiber obtained in Example 159 (1) were piled up by turns.
The laminate was hot pressed at 100 kg/cm2 at 400C to obtain a molded material. The molded material was carbo-nized in the same manner as in Example 171. The result-ing material was subjected to four times oE (a) the impregnation with the reaction product of Example 171 (2) and (b) carbonization, in the same manner as in Example 171. The resulting composite material had a bulk density of 2.00 g/cm3 and a flexural strength of 59 kg/mm . ~hen the composite material was pyrolyzed at 2200C
in argon, the bulk density and flexural strength improved to 2O03 gicm3 abd 63 kg/mm~, respectively~

Example 173 A composite material having a bulk density of 1.20 g/cm3 was obtained in the same manner as in Example 171 except that as a reinforcing fiber there was used the inorganic fiber of Examp:Le 135.
The material was subjected to the impregnation with the reaction product of Example 171 ~2) .in the same manner as in Example 171 to obtain a composite material having a bulk density of 1~96 g/cm3 and a flexural Strength Of 59 kg~mm2 Example 17~
(1) The procedure of Example 171 was repeated except that as a reinforcing fiber there was used the inorganic fiber of Example 136, to obtain a composite mater.ial having a bulk density of ln24 g~cm3.
The material was subjected to the impregnation with the reaction product of Example 171 (2) in the same manner as ln Example 171 to obtain a composite material having a bulk density of 2.03 g/cm3 and a flexural strength of 54 kg/mm2.
Example 175 The composite materials of Examples 171, 172, 173 and 174 were heated for 1 hour in an oven containing air of 600C and then measured for flexural strength~
No strength reduction was seen in any COJnpOSite material.
Example 176 A fiber was prepared using an apparatus of Fig.
1. 250 9 of silicon carbide fine particles (average 3n particle diameter = 0.28 m) was placed in a treactîng tank containing 5,000 cc of ethyl alcohol. Ultrasonic vibration was applied by an ultrasonic applicator 2 to suspend the fine particles in ethyl alcohol and thereby to prepare a treating solution 3.
A continuous fiber bundle 4 of the inorganic fiber obtained in Example 134 was unwound from a bobbin ~ r r~ r~ ~

-- :?,01 --5 and passed through ~he ~reating solution 3 with the passing time controlled at about 15 sec~ by movable eollers 6 and 7. (Durny the passiny, an ultrasonic wave was applled to the treating solution 3 and the solution 3 was stirred with air beir.g blownO) Then~ the continuous fiber bundle was pressed by pressure rollers 8 and 9, wound up by a bobbin 10, and dried at room temperature in air.
Weighin~ of the fiber after the treatment indicated that 7 ~ by volume of the fine particles attached to the fiber.
Example 177 The same treatment as in Exarnple 176 was re-peated except that as the treating solution in the treating tank 1 there was used a slurry obtained by suspending 100 g of silicon carbide whiskers (average diameter: about 0.2/~m, average length: about 100 rn) and 250 9 oE silicon carbide fine particles (average particle diameter: 0.28~ m) in 5,000 cc of ethyl alcohol.
The fiber obtained had a grayish green color.
Observation of the fiber by an electron microsocpe (SEM) indicated that mainly fine particles attached to the surface of each continuous fiber and further mainly whi~kers attached thereonto. IYeighing of the fiber indicated that 10 % by volume of the fine particles and whiskers attached to the fiber.
Separately, a continuous fiber bundle of the inorganic fiber of Example 159 (1) was subjected to the same treatment as above to obtain a fiber to which 8 % by volume of fine particles and whiskers attached.
Example 178 A continuous fiber bundle 4 of the inorganic fiber obtained in Example 135 was treated in the same manner as in Example 176 except that as a treating solution there was used a suspension obtained by sus-pending 100 g of silicon nitride whiskers (average ~0~ 8 diameter: about 0~3 m, average length about 200 m) and 100 g of the above mentioned silicon carbide Eine par-ticles in 5,000 cc of waterO As a result, about 5 % by volume of the fine particles asld whiskers attached to the continuous fine bundle 4O
Example 179 A continuous fiber bundle 4 of the inorganic fiber obtained in Example 136 was passed through a sus-pension obtained by stirring 100 g of silicon carbide fine particles in 500 cc of ethanol, while applying an ultrasonic wave to the suspension. Then, the fiber bundle was passed through a suspension obtained by stir-ring 150 g of silicon nitride whiskers in 500 cc of ethanol, in the same manner and then dried. As a result, about 14 % by volume of the fine particles and whiskers attached to the fiber bundle.
Example 180 The titanium-containing reaction product which is a spinning material for preparation of the inorganic fiber of Example 134 was finely ground and then pyrolyzed at 1300C in an argon current to obtain a fine powder having an average particle diameter of 0.5~ m and con-sisting of crystalline carbon, amorphous carbon and an amorphous material composed mainly of Si-C-O. 100 g of this fine powder was suspended in 500 cc of ethanol by stirring. A continuous fiber bundle 4 of the inorganic fiber obtained in Example 134 was passed through the above suspension while applying an ultrasonic wave to the suspension. The fiber bundle was then passed through a suspension obtained by suspending 150 g of silicon nitride whiskers in 500 cc of ethanol by stirring, in the same manner and then dried. As a result, about 12 ~ of the fine particles and whiskers attached to the fiber bundle.
Example 181 Using the fiber obtained in Example 176 and ~,~ 3 ~ 203 -~an aluminum matrix~ there was pre~pared a unidirectionally reinfQrced FRM. The FRM had a fiber volume fraction (vf) of 50 ~ and a flexural strengkh of 179 kg/mm2 (the ROM
value was 190 kg/mm23.
Example 182 Using the fiber obtained in Example 177 from the inorganic fiber oE Example 13~ and, as a matrix, aluminum containing 5 ~ in total of copper and magnesium, there was prepared a unidirectionally reinforced FRM.
The FRM had a fiber volume fraction of 50 %. Its flexu-ral strength was 185 kgJmm2 and was scarcely different from the ROM value (190 kg~mm ~.
Using the fiber obtained in Example 177 from the inorganic fiber of Example 159 (1) and in the same manner, there was prepared a FRM. The FRM had a flexural strength of 175 kg/mm2, which was scarcely different from the ROM value (173 kg/mm ).
Example 183 The inorganic fiber of Example 134 ~as uni-directionally arranged on a pure aluminum foil (specifiedby JIS 1070) of 0 5 mm in thickness. Thereon was placed another aluminum foil of same quality and size. The laminate was subjected to hot rolling at 670C to prepare a composite foil of fiber and aluminum. The composite 2S foil was piled up in a total sheet number oE 27, was allowed to stand for 10 minutes at 670C under vacuum, and then subjected to hot pressing at 600C to obtain an inorganic fiber-reinforced aluminum composite material.
The inorganic fiber was measured for initial deteriora-tion rate (kg/mm2~sec 1) and fiber strength reduction(%). The composite material was measured for tensile strength in fiber direction (kg/mm2~, tensile modulus of elasticity in fiber direction (t/mm2), interlaminar shear strength (kg/mm ) r tensile strength in direction per-pendicular to fiber (kg/mm2) and fatigue limit/tensile strength. The results are shown in Table 30. The Vf of the composite material was 30 ~ by volume~

For reference, the results of Comparative Example 42 are also shown in Table 30.
Table 3Q
Comparative ~ Example ~2 Initial det2riora~ion rate (kg~mm .sec ~ 0.7 3~2 Fiber s~.rength reduction (%) 51 90 Tensile strength in fiber direction (kg/mm2) 55 25 Tensile modulus of elasticity in f~ber d.irection ~t/mm ) 12.1. 6.5 Interlaminar sh~ar strength (kg/mm ) 5.4 2.2 Tensile strength in direction perpe~dicular to fiber (kg/mm ) 4.3 1.8 Fatigue limit/
tensile strength 0.39 0~25 Example 184 A fiber-reinforced metal was prepared in the same manner as in Example 183 except that there was used an aluminum alloy foil (specified by JIS 6061). The inorganic fiber and the fiber-reinforced metal were measured for the above mentioned properties. The results are shown in Table 31. The results of Comparative Example 43 are also shown in Table 31.

Table 31 Comparative Example 184 Example 43 Initial det~riora~ion rate tkg/mm .sec -) 1.0 3.9 Fiber strellgth reduction t%) 55 95 Interlaminar sh~ar strength ~kg~mm ) 11.2 4.0 Tensile strength in direction perpe~dicular to fiber (kg/mm ) 9.1 3.2 Fatigue limit/
tensile strength 0.42 0.25 Example 185 A plurality of the inorganic fibers of Example 135 were arranged unidirectionally and coated with metallic titanium in a thickness of 0.1-lO~L by the use of a thermal spraying apparatus. This coated inorganic fibee layer was piled up in a plurality of layers with a titanium powder being packed between each two neighboring lQ layers. The laminate was press molded. The molded material was prefired for 3 hours at 520C in a hydrogen atmosphere and then hot pressed at 200 kg/cm2 at 1150~C
for 3 hours in an argon atmosphere to obtain an inorganic fiber-reinforced titanium composite material.
The inorganic fiber was measured for initial deterioration rate (kg/mm2.sec 1) and fiber strength reduction (%), and the composite material was measured for tensile strength in fiber direction (kg~mm2~, interlaminar shear strength ~kg/mm2), tensile strength in direction perpendicular to fiber (kg/mm2) and fatigue limit/tensile strength. The results are shown in Table 32.

The tensile strength in fiber direction, of the composite material was 137 kg/mm2, which was about two t:imes the tensile strength of metallic titanium alone.
The Vf of the composite materia3. was 45 % by volume.
The results of Comparative ~xample 44 are also shown in Table 32~
Table 32 Comparative Example 185 Example 44 Initial det~riora~ion rate ~kg/mm .sec ~ 0.8 3O7 Fiber strength reduction ~%) 49 95 Tensile strength in 2 f.iber direction (kg/mm ) 137 52 Interlaminar sh~ar strength ~kq/mm ) 14.~ 4.7 Tensile strength in direction perpe~dicular to fiber (kg~mm ) 10.1 3.8 Fatigue limit/
tensile strength 0.39 0~20 Example 186 A plurality of the inorganic Eibers of Example 135 were arranged unidirectionally and coated with a titanium alloy ~Ti-6Al-4V) in a thickness of 0.1-10 ~ by the use of a thermal spraying apparatus~ This coated inorganic fiber layer was piled up in a plurality of layers with a titanium powder being packed between each two neighboring layers. The laminate was press molded~
The molded material was prefired for 3 hours at 520C in a hydrogen gas atmosphere and then hot pressed at 200 kg/cm2 at 1150C for 3 hours in an argon atmosphere to obtain an inorganic fiber-reinforced titanium composite material.

' The inorganic fiber Wc15 measured for initial deterioration rate tkg/mm2~sec ]L) and fiber strength reduction (~) r and the composite material was measured for interlaminar shear strength (kg~mm2~, tensile strength in direction perpendicular to fiber ~kg/mm2) and fatigue limititensile strength. The Vf of the composite material was 45 ~ by volume. The results are shown in Table 33.
The results of Comparative Example 45 are also lQ Shown in Table 33.
Table 33 Comparative Example 186 Example 45 Initial det~riora~ion rate (kg/mm .sec ) 0.8 4.0 Fiber strength reduction (%) 50 96 Interlaminar sh~ar strength (kg~mm ) 20.1 7.4 Tensile strength in direction perpe~dicular to fiber (kg/mm ) 16.5 6.D
Fatigue limit/
tensile strength 0.39 0.19 Example 187 On a pure magnesium foil of 0.5 mm in thickness were unidirectionally arranged a plurality of the in organic fibers of Example 136. Thereon was placed another magnesium foil of same quality and size. The laminate was hot rolled at 670C to obtain a composite foil of fiber and magnesium. This composite foil was piled up in a total number of 27, was allowed to stand for 10 minutes at 670C under vacuum, and then was hot pressed at 600C to obtain an inorganic fiber-reinforced magnesium composite material.

T}le inorganic fiber was measured for initial deterioration rate (kg~mm2~sec 1) and fiber strength reduction (~), and the composite material was measured for interlaminar shear strength (kg/mm23, tensile streng-th in direction perpendicular to fiber ~kgimm2) and fatigue limit/tensile strength. The Vf of the composite mater:ial was 30 ~ by volume. The results are shown in Tab~e 34~
The results of Comparative ~xample 46 are also shown in Table 3~O
Table 34 Comparative Example 187 Example 46 Initial det~riora~ion rate ~kg~mm .sec ~ 0~9 4.1 Fiber strength reduction (%) 60 96 Interlaminar sh~ar stren~th (kg/mm ) 4.6 1.5 Tensile strength in direction perpe~dicular to fiber (kg/mm ) 3.7 1.3 Fatigue limit/
tensile strength 0.37 0.21 Example 188 A plurality of the inorganic fibers of Example 136 were undirectionally arranged on a magnesium alloy foil (specified by JIS A 891) of 0.5 mm in thickness.
Thereon was placed another magnesium alloy foil of same quality and size. The laminate was hot rolled at 670C
to prepare a composite foil of fiber and magnesium alloy.
This composite foil was piled up in a total number of 27, was allowed to stand for 10 minutes at 670~C under vacuum, and was hot pressed at 600C to obtain an in-organic fiber-reinforced magnesium composite material.

5;~

The inorganlc fiber was measured for initial deterioration rate ~kg/mm2~sec L) and fiber strength reduction (~, and the composite material was measured for interkaminar shear strength (kg/mm2~, tensile strength in direction perpendicular to fiber (kg/mm2) and fatigue limit/tensile strength~ The Vf of the composite material was 30 ~ by volume. The results are shown in ~able 35.
The results of Comparative Example 47 are also Shown in Table 35, Table 35 Comparative Example 188 Example 47 Initial det~riora~ion rate (kg/mm .sec ) 0.9 4O0 ~iber strength reduction (~) 60 96 Interlamînar sh~ar strength (kg/mm ~ 7.5 2.8 Tensile strength in direction perpe~dicular to fiber (kg/mm ) 6.1 2.2 Fatigue limit~
tensile strength 0.40 0.27 Example 189 An inorganic fiber-reinforced aluminum com-posite material was prepared in the same manner as inExample 183 except that there was used the inorganic fiber of Example 159 (1). The tensile strength of the composite material was about the same as that of the composite material obtained in Example 183, but the tensile modulus of elasticity was greatly improved to 24.5 t/mm . The Vf of the composite material was 30 % by volume.

Claims (14)

1. A polymer composition comprising (A) an organic silicon polymer resulting from random bonding of a plurality of at least one type of bond selected from the group consisting of units re-presented by the following formula (a) ... (a) wherein R1 and R2, independently from each other, represent a hydrogen atom, a lower alkyl group, a phenyl group or a silyl group (-SiH3), either via methylene groups (-CH2-) or both via methylene groups and directly, (B) a polycyclic aromatic compound in the state of a mesophase, a premesophase or a latently anisotro-pic phase, and (C) a polycyclic aromatic compound which is optically isotropic but is not in the state of a premeso phase or a latently anisotropic phase, at least a part of component (A) being chemically bound to component (B) and/or component (C).

2. A polymer composition comprising (A') an organic silicon polymer resulting from random bonding of a plurality of units of at least one kind selected from the group consisting of units of the following formula (a) ... (a) wherein R1 and R2, independently from each other, represent a hydrogen atom, a lower alkyl group, a phenyl group or a silyl group (-SiH3), and at least one unit of formula (b) ... (b) wherein R1 is as defined above, and R3 re-presents -M or -OM, and M represents one equivalent of a metal selected from the group consisting of titaniuum, zirconium and hafnium, via methylene groups (-CH2-) or both via methylene groups and directly, (B) a polycyclic aromatic compound in the mesophase, premesophase or the latently anistropic phase, and (C) an optically isotropic polycyclic aromatic compound which is not in the premesophase or the latently anisotropic phase, part of component (A) being chemically bonded to com-ponent (B) and/for component (C).

3. Fibers having high strength and high modulus of elasticity comprising (i) crystalline carbon oriented substantially in the direction of the fiber axis, (ii) amorphous carbon and/or crystalline carbon oriented in a direction different from the fiber axis direction, and (iii) a silicon-containing component consisting essentially of 30 to 70 % by weight of Si, 20 to 60 % by weight of C and 0.5 to 10 % by weight of O, the propor-tions being based on the total weight of silicon, carbon and oxygen.

4. The fibers of claim 3 in which the crystalline carbon (i) is derived from a polycyclic aromatic compound which is in the mesophase state (optically anisotropic).

5. The fibers of claim 3 in which owing to the presence of the crystalline carbon (i) a radial struc-ture, an onion structure, a random structure, a core-radial structure, a skin onion structure or a mosaic structure is imparted to the cross-section of the fibers.

6. The fibers of claim 3 in which the amorphous carbon and/or the crystalline carbon (ii) is derived from an optically isotropic polycyclic aromatic compound.

7. The fibers of claim 3 in which the silicon-containing component (iii) is an amorphous phase, or an aggregate consisting essentially of a crystalline fine particulate phase composed of crystalline SiC and amor-phous SiOx wherein 0<x<2).

8. The fibers of claim 7 in which the crystalline particulate phase consisting essentially of crystalline SiC has a particle diameter of not more than 500 angstrom.

9. Fibers having high strength and high modulus comprising (i) crystalline carbon oriented substantially in the direction of the fiber axis, (ii) amorphous carbon and/or crystalline carbon oriented in a direction different from the direction of the fiber axis, and (iii') a silicon-containing component sub-stantially composed of 0.5 to 45 % by weight of a metal selected from titanium, zirconium and hafnium, 5 to 70 %
by weight of Si, 20 to 40 % by weight of C and 0.01 to 30 % by weight of O, the proportions being based on the total weight of said metal, silicon, carbon and oxygen.

10. The fibers of claim 9 in which the crystalline carbon (i) is derived from a polycyclic aromatic compound which is in the mesophase state (optically anisotropic).

11. The fibers of claim 9 in which owing to the presence of the crystalline carbon (i), a radial struc-ture, an onion structure, a random structure, a core-radial structure, a skin onion structure or a mosaic structure is imparted to the cross-section of the fibers.

12. The fibers of claim 9 in which the amorphous carbon and/or the crystalline carbon (ii) is derived from an optically isotropic polycyclic aromatic compound.

13. The fibers of claim 9 in which the silicon-containing component (iii)' is an amorphous phase, or an aggregate consisting essentially of a crystalline par-ticulate phase composed of silicon, carbon and a metal selected from the group consisting of titanium, zirconium and hafnium and an amorphous phase of SiOy (0<y<2) and MOz (M=Ti, Zr or Hf and 0<z<2).

14. The fibers of claim 13 in which the crystalline particulate phase has crystalline SiC, MC (M is defined as above), a solid solution of crystalline SiC and MC, and MC1-x (0<x<1) and has a particle diameter of not more than 500 angstrom.