CN1798855A - Advanced erosion resistant oxide cermets - Google Patents

Abstract

A cermet composition and method for its manufacture represented by the formula (PQ) (RS) comprising: a ceramic phase (PQ) and a binder phase (RS) wherein, P is a metal selected from the group consisting of Al, Si, Mg, Ca, Y, Fe, Mn, Group IV, Group V, Group VI elements, and mixtures thereof, Q is oxide, R is a base metal selected from the group consisting of Fe, Ni Co, Mn and mixtures thereof, S consists essentially of at least one element selected from Cr, Al and Si and at least one reactive wetting element selected from the group consisting of Ti, Zr, Hf, Ta, Sc, Y, La, and Ce.

Description

Advanced erosion resistant oxide cermets

Technical field

The present invention is broadly directed to sintering metal, particularly contains the cermet compositions of metal oxide.These sintering metals are applicable to the high-temperature applications of the material that need have excellent resistance to fouling and erosion resistance.

Background technology

Erosion resistant material can be used for suffer erosion many Application Areass of power of surface.For example, refinery process vessel walls and the internals that are exposed in various chemistry and petroleum environments in the aggressive fluids that contains hard solids (for example catalyst particle) can suffer erosion and corrode.The material degradation (especially at high temperature) of protecting these containers and internals against erosion and corrosion to cause is a technological challenge.For needing protection in order to avoid be subjected to the most serious erosion and corrosive assembly; for example be used for solids and fluid are flowed the isolating inner cyclonic separator inwall of (for example being used for the inside cyclonic separator with catalyst particle and the isolating fluidized bed catalytic cracker of process fluid (FCCU)), what use at present is refractory liner.The prior art of erosion resistant material is the chemically combined alumina refractory of casting.These can be cast alumina refractory and are applied on the surface that needs protection, and sclerosis and adhere on the surface by metal crab-bolt (anchor) or metal reinforcement when thermofixation.The aluminum oxide castable refractory is attached on other refractory surfaces easily.A kind of typical chemical constitution of commercially available chemical bond aluminum oxide castable refractory is 80.0 weight %Al ₂O ₃, 7.2 weight %SiO ₂, 1.0 weight %Fe ₂O ₃, 4.8 weight %MgO/CaO, 4.5 weight %P ₂O ₅Be subjected to the very big restriction of the excessive mechanical wear of lining that causes by high-velocity particles bump, mechanical disruption (cracking) and spallation (spallation) work-ing life of the refractory liner under the prior art situation.Therefore, for high-temperature applications, need have the excellent anti-erosion and the material of corrosion resistance properties.Cermet compositions of the present invention has satisfied this needs.

Ceramic-metal composite material is known as sintering metal.For high rigidity and fracture toughness property suitably the sintering metal with enough chemical stabilities of design the resistance to fouling more much higher than refractory materials well known in the prior art can be provided.Sintering metal contains ceramic phase and tackiness agent mutually usually, and generally uses powder metallurgy technology to make, and wherein metal and ceramic powder is mixed, compacting and high temperature sintering to be to form closely knit briquetting.

The present invention includes novel, improved cermet compositions.

The present invention also comprises the suitable cermet compositions of at high temperature using.

In addition, the present invention includes a kind of improved protective money metal surface avoids corroding and corroding method under hot conditions.

According to following detailed description, can be well understood to these purposes and other purpose.

Brief summary of the invention

A specific embodiments of the present invention comprises the cermet compositions shown in a kind of formula (PQ) (RS), and it comprises ceramic phase (PQ) and tackiness agent (RS) mutually, wherein

P is the metal that is selected from the group of being made up of Al, Si, Mg, Ca, Y, Fe, Mn, IV family, V family, VI family element and composition thereof,

Q is an oxide compound,

R is the base metal that is selected from the group of being made up of Fe, Ni, Co, Mn and composition thereof,

S mainly comprises at least a reactivity wetting (wetting) element that is selected from least a element among Cr, Al and the Si and is selected from the group of being made up of Ti, Zr, Hf, Ta, Sc, Y, La and Ce.

Brief description of drawings

Fig. 1 has shown contact angle (θ) data of modification 304 stainless steels (M304SS) that contain different concns Zr/Hf on sapphire C (0001) planar substrate.

Fig. 2 a and 2b are the synoptic diagram according to wetting step of the present invention.

Fig. 3 is the compound X ray picture of acquisition in the scanning electron microscopy (SEM) at aluminum oxide and M304SS interface after the wetting experiment.

The 70 volume %Al that Fig. 4 is to use 30 volume %M304SS tackiness agents to make ₂O ₃Ceramic-metallic SEM figure.

Fig. 5 is ceramic-metallic transmission type microscope (TEM) figure same as shown in Figure 4.

The 70 volume % sheet Al that Fig. 6 is to use 30 volume %M304SS tackiness agents to make ₂O ₃Ceramic-metallic SEM figure.

Detailed Description Of The Invention

A component of the cermet compositions of formula (PQ) shown in (RS) is that mark is made the ceramic phase of (PQ). In ceramic phase (PQ), P is the metal that is selected from the group that is comprised of Al, Si, Mg, Ca, Y, Fe, Mn, the IV of family, the V of family that grow the formula periodic table of elements (Long Form of The Periodic Table of Elements), the VI of family element and composition thereof. Q is oxide. Therefore, the ceramic phase (PQ) in the oxide cermets compound is metal oxide. Aluminium oxide Al₂O ₃It is preferred ceramic phase. (PQ) mol ratio of P and Q can not wait for 0.5: 1 to 1: 2.5 in. As the non-restrictive illustrative example, when P=Si, (PQ) can be SiO₂, P wherein: Q is about 1: 2. When P=Al, (PQ) can be Al₂O ₃, wherein P: Q is 1: 1.5. Pottery mutual-assistance oxide cermets has hardness, and has corrosion resistance being up under about 1150 ℃ temperature.

Ceramic-metallic ceramic phase (PQ) preferably is dispersed in the adhesive phase (RS). The diameter of dispersed ceramic particles is preferably 0.5 to 7000 micron. More preferably, diameter is 0.5 to 3000 micron. Dispersed ceramic particles can have any shape. Some non-limitative examples comprise sphere, ellipse, polyhedron, distorted spherical, distorted ellipsoidal and distortion polyhedron. Particle size diameter refers to the measurement result to the major axis of particle of 3D shape. Can use microscopy to measure granularity, for example optical microscopy (OM), scanning electron microscopy (SEM) and transmission-type EM (TEM).

In another specific embodiments of the present invention, (PQ) be mutually tabular alumina. Tabular alumina is the coarse-grain α-Al of closely knit fire-resistant gathering, good sintering₂O ₃ The sheet title forms from its hexagon flat crystal. The alumina base castable refractory is aggregate form normally. By in erosion process, load being delivered to ceramic phase (PQ) effectively from adhesive phase (RS), use the cermet of tabular alumina manufacturing can have excellent mechanical performance.

Another component of the oxide cermets compound of formula (PQ) shown in (RS) is that mark is made the adhesive phase of (RS). In this adhesive phase (RS), R is the base metal that is selected from the group that is comprised of Fe, Ni, Co, Mn and composition thereof. S is the fused metal that mainly comprises at least a element that is selected from Cr, Al and Si and be selected from the wetting element of at least a reactivity of the group that is comprised of Ti, Zr, Hf, Ta, Sc, Y, La and Ce. The gross weight of Cr, Al, Si and composition thereof is about at least 12 % by weight of adhesive (RS) weight. About 0.01 % by weight that reactive wetting element is binder wt is to about 2 % by weight, and preferably approximately 0.01 % by weight is to about 1 % by weight. Fused metal S may further include the anticorrosive element that is selected from the group that is comprised of Al, Si, Nb, Mo and composition thereof. Anticorrosive element provides excellent corrosion resistance. Reactive wetting element provides better wetability by the contact angle that reduces between ceramic phase (PQ) and the hot-melt adhesive phase (RS) in 1500 ℃ to 1750 ℃ temperature range. A kind of interpolation for example method of the reactive wetting element of Ce and La and so on is to add the mishmetal of appropriate amount. Mishmetal is the rare earth element in the long formula periodic table of elements that mixes, and is known to persons of ordinary skill in the art. These elements can the work in-process oxide and metal dust mixed process in add with pure element, perhaps can be to mix part metals powder before with oxide powder.

In the oxide cermets compound, adhesive phase (RS) accounts for 5 to 70 volume % of cermet volume, preferred 5 to 45 volume %, more preferably 10 to 30 volume %. The mass ratio of R and S is 50/50 to 90/10 not wait. In a preferred specific embodiments, chromium content is at least 12 % by weight of adhesive (RS) weight in the adhesive phase (RS). In another preferred specific embodiments, in the adhesive phase (RS) total content of zirconium and hafnium be adhesive mutually about 0.01 % by weight of (RS) gross weight to about 2.0 % by weight.

Cermet compositions may further include second oxide compound (P ' Q), and wherein P ' is selected from the group of being made up of Al, Si, Mg, Ca, Y, Fe, Mn, Ni, Co, Cr, Ti, Zr, Hf, Ta, Sc, La and Ce and composition thereof.In other words, second oxide compound is by the metallic element deutero-from cermet compositions (PQ) P, R, S and mixture thereof (RS).P ' can not wait for 0.5: 1 to 1: 2.5 with the ratio of Q in (P ' Q).The ceramic phase cumulative volume comprises (PQ) and second oxide compound (P ' Q) in the sintering metal of the present invention.In the oxide cermets mixture, (PQ)+(P ' Q) account for about 30 to 95 volume % of sintering metal volume.Preferably account for about 55 to 95 volume % of sintering metal volume.More preferably account for 70 to 90 volume % of sintering metal volume.

The volume percent of sintering metal phase (and cermet components) does not comprise the pore volume that is caused by porousness.Sintering metal can characterize by the porosity of 0.1 to 15 volume %.Preferably, the porous volume account for the sintering metal volume 0.1 to being lower than 10%.Comprise these holes of porous and preferably do not link to each other, but the pore distribution that conduct is dispersed is in cermet body.The average pore size preferably is equal to or less than the mean particle size of ceramic phase (PQ).

One aspect of the present invention is ceramic-metallic micromorphology.Ceramic phase can disperse with sphere, ellipse, polyhedron, distorted spherical, distorted ellipsoidal and distortion polyhedron shape particle or flap.Preferably, at least 50% dispersed particle is that the particle-spacing of particle between each oxide ceramics particle is the dispersed particle of at least 1 nanometer.Can for example measure particle-spacing of particle by the microscopy of SEM and TEM and so on.

Cermet compositions of the present invention has the anti-erosion and the corrosive nature of raising.Measure erosion rate by heat erosion and the wear test (HEAT) described in the embodiment part of the present disclosure.The erosion rate of oxide cermets of the present invention is lower than every gram SiC eater 1.0 * 10 ^-6Cubic centimetre.Measure erosion rate by the thermo-gravimetric analysis of describing in the embodiment part of the present disclosure (TGA).The erosion rate of oxide cermets of the present invention is lower than 1 * 10 ^-10Gram ²/ centimetre ⁴Second.

Preferably, this sintering metal has greater than about 1.0MPam ^1/2, be preferably greater than about 3MPam ^1/2, more preferably greater than about 5MPam ^1/2Fracture toughness property.Fracture toughness property is the ability of resisting crack propagation in the material under dull loading condition.Fracture toughness property is meant the critical stress intensity factor when crackle begins to spread in an unstable manner in material.The loading (wherein on the tension side of crooked sample precrack being arranged) of preferred use three-point bending geometric format is measured fracture toughness property with Theory of Fracture Mechanics.Mainly be earlier paragraphs described ceramic-metallic (RS) the of the present invention mutual-assistance its have this specific character.

Than using suitable ceramic powder and binder powders to make starting material, make cermet compositions with volume required by general powder metallurgy technology (for example mix, grinding, compacting, sintering and cooling).These powder are ground in ball milling in the presence of organic liquid (for example ethanol), to being enough to make the mutually abundant dispersive time of these powder.Remove liquid, and, place punch die and be pressed into green compact the ground powder for drying.Then with the gained green compact be higher than about 1200 ℃ until about 1750 ℃ sintering temperature about 10 minutes to about 4 hours.This sintering operation preferably carries out at inert atmosphere or under vacuum.For example, inert atmosphere can be an argon gas, and reducing atmosphere can be a hydrogen.After this, make the sintered compact cooling, be cooled to envrionment conditions usually.Prepare sintering metal according to method described herein, can make the sintering metal piece that thickness surpasses 7 millimeters.

Another aspect of the present invention is to avoid making intermetallic precipitations thing (for example known δ phase of field of metallurgy those of ordinary skill) embrittlement.Oxide cermets of the present invention contains this embrittlement phase that preferably is lower than about 5 volume %.Containing earlier paragraphs described (PQ) makes it have this specific character with (RS) sintering metal of the present invention mutually.

A ceramic-metallic feature of the present invention is their microstructural stability, even also be so at elevated temperatures, this makes them be particularly suitable for the protective money metal surface to avoid under about 1150 ℃ corroding being up to.This stability can be used them to surpass the time in 2 years, for example about 2 years to about 10 years.On the contrary, many known sintering metals can change at elevated temperatures, form the phase that ceramic-metallic character is had disadvantageous effect.

Ceramic-metallic high-temperature stability of the present invention makes them be applicable to the Application Areas of present use refractory materials.Suitable purposes non-limiting enumerated and comprises the lining that is used for process vessel, transfer line, cyclonic separator the fluid-solid cyclonic separator of the cyclonic separator of the used fluidized bed catalytic cracker of rendering industry (for example), grid inserts, thermowell, valve body, guiding valve valve and conduit, catalyst regenerator etc.Therefore, by provide one deck cermet compositions layer of the present invention to protect for this surface to be exposed to corrode or corrosive environment under, metallic surface under especially about 300 ℃ to about 1150 ℃.Can sintering metal of the present invention be fixed on the metallic surface by mechanical means or by welding.

Embodiment

The mensuration of volume percent:

Measure the volume percent of each phase, component and pore volume (or porous) by 2 dimension area fractions by scanning electron microscopy.At the enterprising line scanning electron microscopic of agglomerating cermet specimens (SEM), to obtain preferred secondary electron image of amplifying 1000 times.For the zone of SEM scanning, use energy distributing x-ray spectrometry (EDXS) to obtain the X ray point image.Five adjacent areas at sample carry out SEM and EDXS analysis.Use image analysis software then: (EDAX Inc.Mahwah, New Jersey 07430 USA) tie up area fractions to 2 of each each phase of area test to EDXImaging/Mapping version 3 .2.Determine the arithmetical av of area fraction by five measuring results.Determine volume percent (volume %) by the average area mark being multiply by 100 then.Volume % shown in the embodiment has for recording the phasor that is lower than 2 volume %+/-50% precision, have for recording the phasor that equals greater than 2 volume %+/-20% precision.

The mensuration of weight percent:

By standard EDXS assay sintering metal mutually in the weight percent of each element.

Add following non-limiting examples with further elaboration the present invention.

Embodiment 1: reactive wetting

The purposes that adds reactive wetting element in tackiness agent is to promote hot-melt adhesive wetting on pottery by reducing contact angle.Carrying out contact angle measures to quantize wetting phenomena.The alloy binder that will contain the reactive wetting element (i.e. the Hf of the Zr of 0.9 weight % and 0.4 weight %) that accounts for the different amounts of binder wt places the top of monocrystalline polishing substrate (being C (0001) plane sapphire), and at high vacuum furnace (1 * 10 ^-6Torr) be heated to 1700 ℃ in and reach 10 minutes.After sample is cooled to envrionment temperature, measure contact angle by the cross section electron microscopy then.As an example, the contact angle data rows of 304SS is in Fig. 1, and it has shown that contact angle changes and the funtcional relationship of the various concentration of Zr/Hf.This figure shows that the Zr/Hf of 0.1 weight % reduces to 33 ° with contact angle from 160 °.Fig. 2 a and 2b have shown according to wetting step of the present invention.Fig. 3 is at high vacuum furnace (1 * 10 ^-6Torr) carry out wetting experiment after 10 minutes with 1700 ℃ in, (Fe (surplus): 18.2Cr:8.7Ni:1.3Mn:0.9Zr:0.42Si:0.4Hf) the adhesive interface place uses the compound X ray picture that SEM obtains, and wherein scale bar is represented 20 microns at aluminum oxide-M304SS.In the figure, tackiness agent is dark mutually with aluminum oxide.Be light color as the reaction product of mixing Zr/Hf oxide compound phase.

Embodiment 2: raw material powder and erosion test

Obtain alumina powder by various sources.Table 1 has been listed the alumina powder that is used for high temperature resistance erosion/corrosion oxide cermets.

Table 1

Company	Rank	Purity	Granularity
				Alfa Aesar	α-Al 2O 3	99.99％	1 micron
Alcoa	Tabular alumina T-64	99.4％	-8 sieve meshes
				Alcoa	Tabular alumina T-64	99.4％	The 3-6 sieve mesh
Alcoa	Tabular alumina T-64	99.4％	The 6-14 sieve mesh
				Alcoa	Tabular alumina T-64	99.4％	The 8-14 sieve mesh
Alcoa	Tabular alumina T-64	99.4％	The 14-28 sieve mesh
				Alcoa	Tabular alumina T-64	99.4％	The 28-48 sieve mesh

(Neath UK) obtains to pass through the metal alloy powders that the argon gas atomization prepares from Osprey Metals.By traditional breaking method the size of metal alloy powders is brought down below 20 microns, preferably is lower than 5 microns granularity, wherein surpass 95% alloy binder powder and sifting out below 16 microns.As an example, the M304SS powder that uses in this experiment is to surpass the 96.2% alloy binder powder that is sifting out below 16 microns.

Measure the volume of worn sintering metal, refractory materials or contrast material of per unit mass eater particle (this eater particle is the particle of being carried secretly by air-flow with regulation mean particle size and shape), as erosive velocity, unit is cubic centimetre/gram (for example＜0.001 cubic centimetre/1 kilogram of SiC).The speed of eater material and size distribution, eater, mass flux, angle of attack and erosion test temperature and chemical environment can influence erosion.

Measure ceramic-metallic erosion loss by heat erosion and wear test (HEAT).About 2 square inches of sizes, about 0.5 inch thick cermet specimens piece are weighed, be accurate to ± 0.01 milligram.Make the center of this sample blocks one side be subjected to the processing of the SiC particle of 1200 gram/minute of being carried secretly by airstream, it is 0.5 inch riser tube that this airstream comes from diameter, and wherein the end-to-end distance of riser tube is from 1 inch of target disc.As 58 microns of eater have angle SiC particle be 220 granularity #1 level black silicon carbide (UK Abrasives, Inc., Northbrook, IL).The speed that eater clashes on the sintering metal target is 45.7 meter per seconds (150 feet per seconds), and the gas pickling logistics is to be 45 ° ± 5 °, preferred 45 ° ± 2 ° between riser tube main shaft and sample disc surface in the angle of impingement on the target compound.For all tests, carrier gas all is a warm air.Erosion test in the HEAT device was carried out 7 hours under 732 ℃ (1350 °F).After finishing the process-exposed under eater and being cooled to envrionment temperature, cermet specimens is weighed once more, be accurate to ± 0.01 milligram, to determine weight loss.Erosive velocity equals the worn material volume of per unit mass eater particle that air-flow is carried secretly, and unit is a cubic centimetre/gram.Improvement in the table 2 is meant and standard substance RESCOBOND ^TMAA-22S (RescoProducts, Inc., Pittsburgh, 1.0 value PA) is compared, and corrodes the reduction of the weight loss that causes.AA-22S generally includes at least 80.0 weight %Al ₂O ₃, 7.2 weight %SiO ₂, 1.0 weight %Fe ₂O ₃, 4.8 weight %MgO/CaO, 4.5 weight %P ₂O ₅The Photomicrograph of erosion surface obtains by electron microscopy, is used for determining loss mechanism.The eater particle that HEAT experimental measurement aggressiveness is very strong.More typical particle is softer, and produces lower erosion rate.For example, the FCCU catalyzer is based on hydrated aluminium silicate, and its ratio aluminum oxide is soft, and aluminum oxide is much softer than SiC again.

Embodiment 3: alumina modified 304SS sintering metal

Disperseing 70 volume % mean diameters with ethanol in the HDPE grinding pot is α-Al of 1 micron ₂O ₃Powder (99.99% purity is from Alfa Aesar) and 30 volume % mean diameters are 6.7 microns modification M304SS powder (Osprey Metals, 96.2% is sifting out below-16 microns).Zirconium white (YTZ) ball of strengthening with yttrium oxide in ball milling (10 millimeters of diameters are from Tosoh Ceramics) mixed powder 24 hours with 100rpm in ethanol.In vacuum drying oven,, from mixed powder, remove ethanol with 130 ℃ of heating 24 hours.With 5,000psi is with the exsiccant powder pressing in the punch die of 40 mm dias in uniaxial hydraulic press (SPEX 3630AutomatedX-press).In argon gas, the disc green compact made are warming up to 400 ℃ with 25 ℃/minute speed, and keep 30 minutes to remove residual solvent at 400 ℃.Then in high vacuum (10 ^-6Torr) in disc is heated to 1700 ℃ and kept 1 hour at 1700 ℃.Cool the temperature to-15 ℃/minute speed then and be lower than 100 ℃.

The gained sintering metal contains:

I) mean particle size of 70 volume % is about α-Al of 4 microns ₂O ₃

Ii) the mean particle size of 1 volume % is about 0.7 micron the 2nd Zr/Hf oxide compound

The iii) poor Zr/Hf alloy binder of 29 volume %.

Table 2 has been summarized the ceramic-metallic erosion loss that HEAT records.Be about at least 45.7 meter per seconds (150 feet per second), angle of attack when being about 45 degree and temperature and exposing at least 7 hours for 10 microns of 1200 gram/minute of about at least 732 ℃ (1350) to 100 micron SiC particles in speed in air, cermet compositions shows and is lower than about 1 * 10 ^-6The erosion rate of cubic centimetre/gram loss.

Table 2

Sintering metal (embodiment)	Starting weight (gram)	Final weight (gram)	Weight loss (gram)	Tap density (gram/cubic centimetre)	Eater (gram)	Corrode (cubic centimetre/gram)	Improve [(stdn erosion) -1]
								Al 2O 3-30 volume %M304SS	16.6969	14.7379	1.9590	5.130	5.04E+5	7.5768E-7	1.4

Fig. 4 is the Al according to present embodiment processing ₂O ₃Ceramic-metallic SEM image, wherein scale bar is represented 10 microns.In this image, Al ₂O ₃Be dark mutually, tackiness agent is light color mutually.Also show the 2nd Zr/Hf oxide compound phase that makes new advances at the interface at tackiness agent/aluminum oxide.Fig. 5 is the TEM image of institute's favored area among Fig. 4, and wherein scale bar is represented 1 micron.In this image, the 2nd new Zr/Hf oxide compound is dark at the interface at tackiness agent/aluminum oxide.The metallic element of the second metal oxide phase (M) comprises about 70 weight %Zr:30 weight %Hf.Because the middle mutually Zr/Hf of the precipitation of the 2nd Zr/Hf oxide compound phase, tackiness agent reduces.

Embodiment 4: alumina modified 304SS sintering metal

With 70 volume % tabular aluminas (99.4% purity, from Alcoa, 90% sifts out below 8 orders) and 30 volume % mean diameters is that 6.7 microns M304SS powder (Osprey Metals, 96.2% is sifting out below-16 microns) places the HDPE grinding pot.Without liquid medium, powder was mixed 24 hours with 100rpm in ball milling.With 1,000psi is with the mixed powder compacting in the alumina crucible of 40 mm dias.Then in high vacuum (10 ^-6Torr) the ball sheet with compacting in is heated to 1700 ℃, and keeps 1 hour at 1700 ℃.Cool the temperature to below 100 ℃ with-15 ℃/minute speed then.

The gained sintering metal contains:

I) the Al of 70 volume % with various granularities (8 order) ₂O ₃

Ii) the mean particle size of 1 volume % is about 1 micron the 2nd Zr/Hf oxide compound

The iii) poor Zr/Hf alloy binder of 29 volume %.

The compound X ray picture that Fig. 6 is to use SEM to obtain, wherein scale bar is represented 20 microns.In this image, Al ₂O ₃Be dark mutually, tackiness agent is light color mutually.Also demonstrate the 2nd Zr/Hf oxide compound phase with white at the interface by the wetting generation of reactivity at tackiness agent/aluminum oxide.

Embodiment 5: intensive alumina modified 304SS sintering metal

Can select the ceramic particle sorting to obtain intensive thing.In this case, use the measurement standard of mesh size as granularity.Sieve the particle of all size to obtain described particle by sieve (screen cloth).Screen size is represented the number of aperture on the sieve per square inch.In other words, mesh size 100 can use following sieve: in level and the every linear inch of vertical direction 10 wire are arranged all, produce 100 perforates per square inch."+" of mesh size front expression particle is retained on the sieve and greater than sieve aperture."-" expression particle of mesh size front is by sieve and less than sieve aperture.For example ,-48 order represents that particle passes through 48 orders (388 microns) sieve and less than its perforate.Common 90% or more multiparticle in specific sieve mesh.Usually, mesh size is by two numerals (just 28/48) expression.Size range falls into two sieves in other words.Top sieve has 28 perforates per square inch, and end sieve has 48 perforates per square inch.For example, the size range of a collection of filler can be dwindled, so that it contains 388 microns to 707 microns particle.At first, be the sieve screening of 28 (28 perforates per square inch) by mesh size, pass through less than 707 microns particles.Then, after first sieve, using mesh size is second sieve of 48 (48 perforates per square inch), passes through less than 388 microns particles.Between two sieves, can obtain 388 microns to 707 microns size range.Then this batch pottery is illustrated as having 28/48 mesh size.Table 3 has shown the screening formulation of intensive pottery of the present invention.

Table 3

The pottery mesh size	Proximate micron size (micron)	Volume fraction (%)
			3/6	7097～3350	20
6/14	3350～1680	15
			8/14	2380～1680	12
14/28	1680～707	7
			28/48	707～388	15
-48	-388	10
			-100	-149	10
-325	-44	6
			-635	-20	5
Total amount		100

70 volume % are placed the HDPE grinding pot based on the M304SS powder (Osprey Metals, 96.2% is sifting out below-16 microns) that tabular alumina (99.4% purity is from the Alcoa) formulation and the 30 volume % mean diameters of table 3 are 6.7 microns.Without liquid medium, powder was mixed 24 hours with 100rpm in ball milling.With 1,000psi is with the mixed powder compacting in the alumina crucible of 40 mm dias.Then in high vacuum (10 ^-6Torr) the ball sheet with compacting in is heated to 1700 ℃, and keeps 1 hour at 1700 ℃.Cool the temperature to-15 ℃/minute speed then and be lower than 100 ℃.

The gained sintering metal contains:

I) the Al of 70 volume % with various granularities ₂O ₃

Ii) the mean particle size of 1 volume % is about 1 micron the 2nd Zr/Hf oxide compound

The iii) poor Zr/Hf alloy binder of 29 volume %.

Embodiment 6: corrosion test

Each sintering metal to embodiment 3,4 and 5 carries out oxidation test.Program thereby is as follows:

1) cermet specimens with about 10 mm square, about 1 mm thick is polished to 600 granularity diamond precision machined surfaces, and cleans in acetone.

2) in thermogravimetric analyzer (TGA), this sample is exposed in the air of 100 cc/min under 800 ℃ then.

3) step (2) was carried out under 800 ℃ 65 hours.

4) after 65 hours, make sample be cooled to envrionment temperature.

5) measure the thickness of oxide skin by the cross section microscopy of corrosion surface.

Preferentially the thickness of the oxide skin that forms on mutually at tackiness agent is about 0.5 micron to about 1.5 microns.When exposing at least 65 hours under 800 ℃ in 100 cc/min air, cermet compositions shows and is lower than about 1 * 10 ^-11Gram ²/ centimetre ⁴Erosion rate and the mean thickness of second are lower than 30 microns oxide skin.

Claims (17)

1. the cermet compositions of a formula (PQ) shown in (RS), it comprises ceramic phase (PQ) and tackiness agent (RS) mutually, wherein

P is the metal that is selected from the group of being made up of Al, Si, Mg, Ca, Y, Fe, Mn, IV family, V family, VI family element and composition thereof,

Q is an oxide compound,

R is the base metal that is selected from the group of being made up of Fe, Ni, Co, Mn and composition thereof,

S mainly comprises the wetting element of at least a reactivity that is selected from least a element among Cr, Al and the Si and is selected from the group of being made up of Ti, Zr, Hf, Ta, Sc, Y, La and Ce.

2. the cermet compositions of claim 1, wherein ceramic phase (PQ) accounts for about 30 to 95 volume % of sintering metal volume.

3. the cermet compositions of claim 2, wherein the mol ratio of P: Q can not wait for 0.5: 1 to 1: 2.5 in the ceramic phase (PQ).

4. the cermet compositions of claim 1, wherein (PQ) accounts for about 55 to 95 volume % of sintering metal volume.

5. the cermet compositions of claim 1, wherein said ceramic phase (PQ) are that 0.5 micron to 7000 microns spheroidal particle is distributed in the tackiness agent phase (RS) as diameter.

6. the cermet compositions of claim 1, wherein tackiness agent phase (RS) accounts for 5 to 70 volume % of sintering metal volume, and the mass ratio of R and S is 50/50 to 90/10.

7. the cermet compositions of claim 6, the gross weight of wherein said Cr, Al and Si and composition thereof is the tackiness agent at least 12 weight % of (RS) weight mutually.

8. the cermet compositions of claim 1, the wetting element of described reactivity that wherein is selected from the group of being made up of Ti, Zr, Hf, Ta, Sc, Y, La and Ce accounts for tackiness agent 0.01 to the 2 weight % of (RS) gross weight mutually.

9. the cermet compositions of claim 1, it further comprises second oxide compound (P ' Q), and wherein P ' is selected from the group of being made up of Al, Si, Mg, Ca, Y, Fe, Mn, Ni, Co, Cr, Ti, Zr, Hf, Ta, Sc, La and Ce and composition thereof.

10. the cermet compositions of claim 1, it has and is lower than about every gram SiC eater 1 * 10 ^-6The erosion rate of cubic centimetre.

11. the cermet compositions of claim 1, it has and is lower than about 1 * 10 when exposing at least 65 hours under 800 ℃ in the air of 100 cc/min ^-11Gram ²/ centimetre ⁴Erosion rate or the mean thickness of second are lower than 30 microns oxide skin.

12. the cermet compositions of claim 1, it has and is lower than about every gram SiC eater 1 * 10 ^-6The erosion rate of cubic centimetre, and when exposing at least 65 hours under 800 ℃ in the air of 100 cc/min has and is lower than about 1 * 10 ^-11Gram ²/ centimetre ⁴Erosion rate or the mean thickness of second are lower than 30 microns oxide skin.

13. the cermet compositions of claim 1, it contains the embrittlement phase of the about 5 volume % that are lower than the sintering metal volume.

14. the cermet compositions of claim 1, it has greater than about 1.0MPam ^1/2Fracture toughness property.

15. a protection is in the method that is up to the metallic surface that suffers erosion under 1150 ℃ the temperature, this method is included as this metallic surface cermet compositions according to claim 1-14 is provided.

16. a protection is exposed to the method for the metallic surface in the erosion material under 300 ℃ to 1150 ℃ temperature, this method is included as this metallic surface cermet compositions according to claim 1-14 is provided.

17. the method for claim 15, wherein said surface comprises the internal surface of liquid-solid cyclonic separator.

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