JPH055799B2 - - Google Patents
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- Publication number
- JPH055799B2 JPH055799B2 JP22774285A JP22774285A JPH055799B2 JP H055799 B2 JPH055799 B2 JP H055799B2 JP 22774285 A JP22774285 A JP 22774285A JP 22774285 A JP22774285 A JP 22774285A JP H055799 B2 JPH055799 B2 JP H055799B2
- Authority
- JP
- Japan
- Prior art keywords
- gas
- whiskers
- furnace
- reaction
- sio
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- 239000007789 gas Substances 0.000 claims description 29
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 15
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 15
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 235000012239 silicon dioxide Nutrition 0.000 claims description 7
- 239000002994 raw material Substances 0.000 claims description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 5
- 239000000377 silicon dioxide Substances 0.000 claims description 5
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 4
- 239000003575 carbonaceous material Substances 0.000 claims description 3
- 229910001873 dinitrogen Inorganic materials 0.000 claims description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims 2
- 229910002092 carbon dioxide Inorganic materials 0.000 claims 1
- 239000001569 carbon dioxide Substances 0.000 claims 1
- 229910052814 silicon oxide Inorganic materials 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 description 24
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 22
- 238000000034 method Methods 0.000 description 11
- 239000000843 powder Substances 0.000 description 10
- 229910004298 SiO 2 Inorganic materials 0.000 description 9
- 239000000835 fiber Substances 0.000 description 8
- 239000000203 mixture Substances 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 241000209094 Oryza Species 0.000 description 4
- 235000007164 Oryza sativa Nutrition 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 239000010903 husk Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 235000009566 rice Nutrition 0.000 description 4
- 239000013078 crystal Substances 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000000945 filler Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000011863 silicon-based powder Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 238000005121 nitriding Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910021489 α-quartz Inorganic materials 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
Description
産業上の利用分野
本発明は窒化ケイ素ホイスカーの製造法に関し
極めて簡単な装置を用い、従来製造困難であつた
長いホイスカーを容易に得ることができる方法に
関する。得られた長いホイスカーは引張強さが著
しく高いので、FRM等複合材料のフイラーとし
て利用することができる。
従来の技術と問題点
窒化ケイ素ホイスカーの製造法については、従
来から種々の方法が提案され、例えば特開昭57−
196711号では、炭化させた籾殻あるいは珪石等珪
酸分を含有し薄肉で空隙のある原料をトレーに充
填し非酸化性雰囲気下で不純物を揮散させた後、
1350〜1450℃の温度域で窒化させることにより窒
化ケイ素ホイスカーを得る方法で、また特開昭58
−172298号は基本的には上記方法と同一で予め原
料ホイスカーに窒化ケイ素粉末を結晶核として付
着せしめて行なうものであり、ホイスカーは炭化
籾殻等原料や窒化ケイ素粉体中に分散しており、
籾殻等を分離除去する必要がある。また得られた
ホイスカーも径0.1〜1.0μm、長さ50μm〜２mm、
アスペクト比10000〜20000と短いものである。
一方、特公昭41−17967号、特公昭50−4480号
に見られる窒化ケイ素ホイスカーの製造法はケイ
素成分を含むガスと窒素ガスないしは窒素を含む
混合ガスの反応により生長せしめるもので、後者
は、反応促進のため特定の金属又は金属化合物を
触媒として用いるものであるが、ケイ素含有ガス
の生成とホイスカー生成反応とを、同時に行なわ
せるため、炉内の温度勾配、混合ガス組成などの
バランスを保つ必要があり、製造に用いる装置が
複雑で工業化上難点がある。
問題点を解決するための手段
本発明者らは、以上の問題点を解決するため、
SiOとCOおよびN2によるSi3N4ホイスカーの製造
法について研究を重ね、SiOの合成反応と、SiO、
COおよびN2からホイスカーを生成、生長せしめ
る反応とを、反応容器内における圧力を変更する
ことにより、それぞれ効果的に進行せしめること
ができ、従つて、この二つの工程を交互に繰返す
ことにより、炉内の炭素質面上に長繊維状の
Si3N4ホイスカーを得られることを見出し反応条
件について検討を重ね、本発明を完成するに至つ
た。
本発明方法は、二酸化ケイ素を原料として窒化
ケイ素ホイスカーを製造する方法において、
(イ) 炉内に置かれた二酸化ケイ素に一酸化炭素ガ
スを1100℃以上、常圧以下で接触させ、一酸化
ケイ素ガスと炭酸ガスの混合ガスを発生させ、
(ロ) 次に、上記炉内に発生した混合ガスに窒素ガ
スを添加し、1100℃以上、常圧以上に保持して
炉内の炭素質面上にホイスカーを生成させる工
程；
とからなり、上記(イ)と(ロ)の工程を少なくとも数回
交互に繰返すことを特徴とするものである。
このようにして、炉内のガス組成、反応条件を
変えることにより、極めて容易に長繊維状の窒化
ケイ素ホイスカーを製造することができる。
次に、上記Si3N4ホイスカーの生成する反応機
構の概略は以下のように考えられる。
炉内の容器に充填されたSiO2粉末はCOガス雰
囲気下で加熱される。1100℃以上に加熱したと
き、COガス圧力を常圧より低くすると、次式に
よりSiOガスが発生する。
SiO2＋CO（ガス）→SiO（ガス）＋CO2（ガス）
……(1)
このSiOガスは以下の反応で窒化ケイ素ホイス
カーを生成する。
3SiO（ガス）＋3C＋2N2→Si3N4（固体）
＋3CO（ガス） ……(2)
3SiO（ガス）＋3C＋2N2→Si3N4（固体）
＋3CO2（ガス） ……(3)
上記(1)式の反応の自由エネルギー△Ｇは、
△Ｇ＝△G゜＋RT1npSiO・pCO2／PCO ……(4)
で示され、反応を進行させるためには右辺第２項
から判る如く減圧状態で行なうことが望ましい。
上記(1)式の反応で充分なSiOが容器内に生成さ
れると、炉内のＣ（SiO2の充填に用いた炭素質容
器、炉壁又は炉内に設けた炭素質面等）と反応
し、(2)式の反応でSi3N4ホイスカーの結晶核が生
成する。所定の温度範囲に維持することで生成核
の上に上記(3)式の反応で同時に、Si3N4ホイスカ
ーが生長し始めると考えられる。この場合、上記
(3)式に相応する反応の自由エネルギー△Ｇは、
△Ｇ＝△G゜RT1n（pCO2）3／（pSiO）3・（pCO）3・（p
N2）2……(5)
であり、反応を進行させるためには、上式右辺第
２項から判る如く常圧より加圧状態の方がSi3N4
ホイスカーの成長が速いと考えられる。
次に本発明をさらに詳しく述べると、反応に使
用されるSiO2粉末は特に純度を規定する必要は
ないが、SiO2分として99％以上が好ましい。粒
度は200μm以下が良い。SiO用Si源として、より
高純度が必要な場合には、金属ケイ素粉末を酸化
して使用することができる。
反応炉及びSiO2粉末の静置容器としては、
1100℃以上の高温になるので、1600℃以上で、好
ましくは2000℃以上で焼成した、例えば黒鉛質の
ものが良い。これは、高温で揮発分が揮発して上
記反応温度で炉内の雰囲気を汚染するものが生じ
ないためである。SiO2粉末は反応炉の底に載置
しても、充填用容器の中に入れて反応炉中に挿入
してもよく、炉材や前記SiO2粉末容器（もし必
要ならば）はSiCやSi3N4等の焼結品でもよい。
次に、Si3N4ホイスカー生成用の炭素質面とし
ては、反応炉炉壁面自体でも、炉壁上にさらに炭
素質材料で被覆し、あるいは炭素質材を炉内に垂
下せしめたものでもよい。但し、Si3N4ホイスカ
ーの長繊維状のものが伸長するための炉内空間は
必要であり、炉の内側の大きさとしては、角形炉
の場合、縦10〜50cm、横10〜50cm長さ20〜200cm
の範囲が目安であるが、もちろん、反応容器の寸
法はこれに限られず、また円筒状容器でもよい。
反応炉内の雰囲気については、1100℃以上、好
ましくは1200〜1600℃の範囲がよく、1100℃以下
では前記(1)式の反応が起り難く、1600℃を超える
と窒化ケイ素ホイスカーの蒸気圧が高くなり収率
が低下するため、前記温度範囲内で反応させる必
要がある。この温度範囲において、炉内を20〜50
℃以内の温度差に保つことが好ましい。
また、本発明は、前記1100℃以上の温度範囲
で、ガス組成を変え、雰囲気圧力を交互に常圧
（１気圧）以下と常圧以上に操作することで窒化
ケイ素ホイスカーの長繊維状のものを得るのであ
るが、常圧以下とは1.0気圧以下で、好ましくは
0.7気圧以下、さらに好ましくは0.4気圧以下が良
い。但し0.2気圧以下では(1)式の反応を促進する
が、炉内に気化したSiOガスを無駄に排出してし
まうので好ましくない。また、常圧以上とは1.1
気圧以上で、好ましくは1.2〜2.0気圧が良く、2.0
気圧以上では炉のシールや耐圧に問題がある。し
かし、そのおそれがなければ、それ以上の気圧で
をよい。
また、常圧以下及び常圧以上に保持する時間は
それぞれ５分〜３時間程度でよく、各工程を各々
数回以上繰返してSi3N4ホイスカーを成長させ
る。なお、反応はSiO2粉末がほとんど無くなる
まで行なつてもよいが、途中で止めてもよいこと
は、もちろんである。
実施例
以下に実施例により、本発明をさらに具体的に
説明する。
実施例
純度99.8％以上の平均粒径2μmの金属ケイ素粉
を0.1N希塩酸で酸化処理した。暖水乾燥後高純
度黒鉛製匡体に前記処理粉体を入れ、雰囲気中に
セツトした。
減圧COガス雰囲気のもとで昇温し、1500℃に
達してから１時間後に、N2ガスを導入し、1.5気
圧とし、２時間保持した。以後２時間毎にCO導
入及び減圧（0.4気圧）、N2導入及び加圧（1.5気
圧）を繰返し、20時間保持した。冷却後、黒鉛容
器内壁に生成した繊維の特性を調べた。結果を次
の第１表に示す。
INDUSTRIAL APPLICATION FIELD The present invention relates to a method for manufacturing silicon nitride whiskers, and relates to a method that uses extremely simple equipment and can easily produce long whiskers, which have conventionally been difficult to manufacture. The obtained long whiskers have extremely high tensile strength and can be used as fillers in composite materials such as FRM. Conventional techniques and problems Various methods have been proposed for manufacturing silicon nitride whiskers, for example, Japanese Patent Application Laid-Open No. 1986-
In No. 196711, carbonized rice husk or silica stone containing thin walled and porous raw materials containing silicic acid are filled into a tray, and after volatilizing impurities in a non-oxidizing atmosphere,
A method of obtaining silicon nitride whiskers by nitriding at a temperature range of 1350 to 1450°C, and also disclosed in JP-A-58
-172298 is basically the same method as above, and is carried out by attaching silicon nitride powder as a crystal nucleus to the raw material whiskers in advance, and the whiskers are dispersed in the raw material such as carbide rice husks or silicon nitride powder.
It is necessary to separate and remove rice husks, etc. The obtained whiskers also have a diameter of 0.1 to 1.0 μm and a length of 50 μm to 2 mm.
It has a short aspect ratio of 10,000 to 20,000. On the other hand, the method for producing silicon nitride whiskers, which can be found in Japanese Patent Publications No. 41-17967 and No. 50-4480, involves the growth of silicon nitride whiskers through the reaction of a gas containing a silicon component and nitrogen gas or a mixed gas containing nitrogen. A specific metal or metal compound is used as a catalyst to promote the reaction, and in order to generate silicon-containing gas and whisker generation reaction at the same time, the temperature gradient in the furnace and the composition of the mixed gas are kept in balance. However, the equipment used for production is complicated, making it difficult to industrialize. Means for Solving the Problems In order to solve the above problems, the present inventors
We have repeatedly researched the production method of Si 3 N 4 whiskers using SiO, CO and N 2 , and have investigated the synthesis reaction of SiO, SiO,
By changing the pressure in the reaction vessel, the reaction of producing and growing whiskers from CO and N 2 can proceed effectively. Therefore, by repeating these two steps alternately, Long fibers are formed on the carbonaceous surface inside the furnace.
They discovered that Si 3 N 4 whiskers could be obtained, and after repeated studies on reaction conditions, they completed the present invention. The method of the present invention is a method for manufacturing silicon nitride whiskers using silicon dioxide as a raw material. (a) Silicon dioxide placed in a furnace is brought into contact with carbon monoxide gas at a temperature of 1100°C or higher and below normal pressure, and silicon monoxide is (b) Next, nitrogen gas is added to the mixed gas generated in the furnace, and the temperature is maintained at 1100°C or above and normal pressure, and the mixture is heated on the carbonaceous surface inside the furnace. generating whiskers; and is characterized by repeating the above steps (a) and (b) alternately at least several times. In this way, long fiber silicon nitride whiskers can be produced very easily by changing the gas composition and reaction conditions in the furnace. Next, the outline of the reaction mechanism for producing the Si 3 N 4 whiskers is considered as follows. SiO 2 powder filled in a container inside the furnace is heated under a CO gas atmosphere. When heated to 1100°C or higher and the CO gas pressure is lower than normal pressure, SiO gas is generated according to the following formula. SiO 2 + CO (gas) → SiO (gas) + CO 2 (gas)
...(1) This SiO gas generates silicon nitride whiskers through the following reaction. 3SiO (gas) +3C+2N 2 →Si 3 N 4 (solid) +3CO (gas) ...(2) 3SiO (gas) +3C+2N 2 →Si 3 N 4 (solid) +3CO 2 (gas) ...(3) Above (1) The free energy △G of the reaction in the equation It is desirable to do so. When enough SiO is generated in the container by the reaction of equation (1) above, carbon in the furnace (carbonaceous container used for filling SiO 2 , furnace wall, carbonaceous surface provided in the furnace, etc.) react, and crystal nuclei of Si 3 N 4 whiskers are generated by the reaction of equation (2). It is thought that by maintaining the temperature within a predetermined range, Si 3 N 4 whiskers begin to grow on the generated nuclei at the same time through the reaction of equation (3) above. In this case, the above
The free energy △G of the reaction corresponding to equation (3) is: △G=△G゜RT1n (p CO2 ) 3 / (p SiO ) 3・(p CO ) 3・(p
N2 ) 2 ...(5), and in order for the reaction to proceed, as can be seen from the second term on the right side of the above equation, it is better to use Si 3 N 4 under pressurized conditions than under normal pressure.
Whisker growth is thought to be rapid. Next, to describe the present invention in more detail, it is not necessary to specify the purity of the SiO 2 powder used in the reaction, but it is preferably 99% or more as SiO 2 powder. The particle size is preferably 200 μm or less. If higher purity is required as the Si source for SiO, metal silicon powder can be oxidized and used. As a reactor and a static container for SiO 2 powder,
Since the temperature is 1100°C or higher, it is preferable to use graphite, for example, fired at 1600°C or higher, preferably 2000°C or higher. This is because volatile matter evaporates at high temperatures and does not pollute the atmosphere in the furnace at the above reaction temperature. The SiO 2 powder can be placed at the bottom of the reactor or inserted into the reactor in a filling container, and the reactor material and the SiO 2 powder container (if necessary) can be filled with SiC or A sintered product such as Si 3 N 4 may also be used. Next, the carbonaceous surface for producing Si 3 N 4 whiskers may be the reactor wall itself, the furnace wall further coated with a carbonaceous material, or a carbonaceous material suspended inside the furnace. . However, a space inside the furnace is required for the long fibers of Si 3 N 4 whiskers to expand, and the inside size of the furnace is 10 to 50 cm long and 10 to 50 cm wide in the case of a rectangular furnace. length 20~200cm
The size of the reaction container is, of course, not limited to this range, and may be a cylindrical container. The atmosphere in the reactor should be at least 1100°C, preferably in the range of 1200 to 1600°C. Below 1100°C, the reaction of formula (1) is difficult to occur, and when it exceeds 1600°C, the vapor pressure of the silicon nitride whiskers will decrease. Since the temperature increases and the yield decreases, it is necessary to carry out the reaction within the above temperature range. In this temperature range, the temperature inside the furnace is 20 to 50
It is preferable to maintain the temperature difference within ℃. In addition, the present invention produces silicon nitride whiskers in the form of long fibers by changing the gas composition and alternately controlling the atmospheric pressure to below normal pressure (1 atm) and above normal pressure in the temperature range of 1100°C or above. However, below normal pressure means below 1.0 atmosphere, preferably below normal pressure.
The pressure is preferably 0.7 atm or less, more preferably 0.4 atm or less. However, if the pressure is lower than 0.2 atm, the reaction of equation (1) will be promoted, but the vaporized SiO gas will be discharged into the furnace unnecessarily, which is not preferable. Also, above normal pressure is 1.1
Atmospheric pressure or higher, preferably 1.2 to 2.0 atm, preferably 2.0 atm.
Above atmospheric pressure, there are problems with the sealing and pressure resistance of the furnace. However, if there is no risk of this happening, higher atmospheric pressure may be used. Further, the time for maintaining the pressure below normal pressure and above normal pressure may be about 5 minutes to 3 hours, respectively, and each step is repeated several times or more to grow Si 3 N 4 whiskers. Note that the reaction may be carried out until almost all SiO 2 powder is consumed, but it is of course possible to stop the reaction halfway. EXAMPLES The present invention will be explained in more detail with reference to Examples below. Example Metallic silicon powder with a purity of 99.8% or more and an average particle size of 2 μm was oxidized with 0.1N diluted hydrochloric acid. After drying with warm water, the treated powder was placed in a high-purity graphite case and set in an atmosphere. The temperature was raised in a reduced pressure CO gas atmosphere, and one hour after reaching 1500°C, N 2 gas was introduced to bring the pressure to 1.5 atm, which was maintained for 2 hours. Thereafter, CO introduction and pressure reduction (0.4 atm), N 2 introduction and pressurization (1.5 atm) were repeated every 2 hours, and this was maintained for 20 hours. After cooling, the characteristics of the fibers formed on the inner wall of the graphite container were investigated. The results are shown in Table 1 below.
【表】
注 (1) 痕跡のα−石英、(2) 痕跡のβ−
Si３N４を含む。
試料１〜５は上記実施例で得られたもので、か
なりの分布を示すものの、長繊維状で、引張強度
が優れていることが示される。
発明の効果
本発明方法によつて得られた長繊維状Si3N4ホ
イスカーの特長は次の通りである。
(a) ホイスカーとしての特性が優れている。
比較のため、市販品の特性を次の第２表に示
す。[Table] Notes (1) Traces of α−quartz, (2) Traces of β−
Contains Si3N4 .
Samples 1 to 5 were obtained in the above examples, and although they show a considerable distribution, they are long fibers and have excellent tensile strength. Effects of the Invention The long-fiber Si 3 N 4 whiskers obtained by the method of the present invention have the following features. (a) Excellent whisker characteristics. For comparison, the properties of commercially available products are shown in Table 2 below.
【表】
これに対し、本発明方法によれば、前記第１
表から得られたものは平均直径は0.5μm以上、
平均長さは５mm以上の長繊維状のものである。
アスペクト比（長さμm／直径μm）で1000〜
500000と従来品より極めて大きい。また引張強
度は200〜1000Kg／mm2と大きな値を示している。
(b) 純度が非常に高い製品が得られる。
籾殻等の原料を用いた従来技術の場合、ホイ
スカーと不純物（Al2O3、CaO、MgO、Fe2O3
その他）ないしは残存原料との分離工程を必要
とするが、本発明による炉から取出したままの
もののＸ線回折で調べた結果は、構造はほとん
どα−Si3N4ホイスカーで、石英の結晶が痕跡
として認められる場合があるが、分離工程なし
で、もし必要としても痕跡の石英除去工程のみ
で極めて高純度のものが得られる。
以上の如く、本発明方法によれば、極めて簡単
な装置を用い、反応時のガス組成、圧力を変更し
た工程を繰返すのみでよく、精密なガス組成や温
度条件の制御のための複雑な装置を必要としな
い。また、得られた長いホイスカーは引張強度が
大でFRM等複合材料用フイラーとして極めて優
れたものである。[Table] In contrast, according to the method of the present invention, the first
Those obtained from the table have an average diameter of 0.5 μm or more,
It is a long fiber with an average length of 5 mm or more.
Aspect ratio (length μm/diameter μm) 1000~
500,000, which is significantly larger than conventional products. Moreover, the tensile strength shows a large value of 200 to 1000 Kg/mm 2 . (b) A product of very high purity is obtained. In the case of conventional technology using raw materials such as rice husks, whiskers and impurities (Al 2 O 3 , CaO, MgO, Fe 2 O 3
However, an X-ray diffraction analysis of the material taken out from the furnace according to the present invention shows that the structure is mostly α-Si 3 N 4 whiskers, with quartz crystals. Although it may be recognized as a trace, extremely high purity can be obtained without any separation process and only by removing the trace of quartz, if necessary. As described above, according to the method of the present invention, it is only necessary to repeat the process by changing the gas composition and pressure during the reaction using an extremely simple device, and it is not necessary to use a complicated device for precisely controlling the gas composition and temperature conditions. does not require. Furthermore, the obtained long whiskers have high tensile strength and are extremely excellent fillers for composite materials such as FRM.
Claims (1)
カーを製造する方法において、 (イ) 炉内に置かれた二酸化ケイ素に一酸化炭素ガ
スを1100℃以上、常圧以下で接触させ、一酸化
ケイ素ガスと炭酸ガスの混合ガスを発生させ、 (ロ) 次に、上記炉内に発生した混合ガスに窒素ガ
スを添加し、1100℃以上、常圧以上に保持して
炉内の炭素質面上にホイスカーを生成させる工
程； とからなり、上記(イ)と(ロ)の工程を少なくとも数回
交互に繰返すことを特徴とする窒化ケイ素ホイス
カーの製造法。[Claims] 1. In a method for producing silicon nitride whiskers using silicon dioxide as a raw material, (a) carbon monoxide gas is brought into contact with silicon dioxide placed in a furnace at a temperature of 1100°C or above and below normal pressure; A mixed gas of silicon oxide gas and carbon dioxide gas is generated, (b) Next, nitrogen gas is added to the mixed gas generated in the above furnace, and the temperature is maintained at 1100°C or higher and above normal pressure to remove the carbonaceous material in the furnace. 1. A method for producing silicon nitride whiskers, comprising: generating whiskers on a surface; and comprising repeating the steps (a) and (b) alternately at least several times.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22774285A JPS6287497A (en) | 1985-10-15 | 1985-10-15 | Production of silicon nitride whisker |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22774285A JPS6287497A (en) | 1985-10-15 | 1985-10-15 | Production of silicon nitride whisker |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6287497A JPS6287497A (en) | 1987-04-21 |
| JPH055799B2 true JPH055799B2 (en) | 1993-01-25 |
Family
ID=16865656
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22774285A Granted JPS6287497A (en) | 1985-10-15 | 1985-10-15 | Production of silicon nitride whisker |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6287497A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5055276A (en) * | 1989-11-15 | 1991-10-08 | Huckins Harold A | Ceramic whisker growing system |
-
1985
- 1985-10-15 JP JP22774285A patent/JPS6287497A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6287497A (en) | 1987-04-21 |
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