JPH0511047B2 - - Google Patents
Info
- Publication number
- JPH0511047B2 JPH0511047B2 JP63107684A JP10768488A JPH0511047B2 JP H0511047 B2 JPH0511047 B2 JP H0511047B2 JP 63107684 A JP63107684 A JP 63107684A JP 10768488 A JP10768488 A JP 10768488A JP H0511047 B2 JPH0511047 B2 JP H0511047B2
- Authority
- JP
- Japan
- Prior art keywords
- silicon nitride
- cmhn
- gas
- reaction
- metals
- 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
Links
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 28
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 26
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 26
- 239000000377 silicon dioxide Substances 0.000 claims description 13
- 239000000843 powder Substances 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 229910052723 transition metal Inorganic materials 0.000 claims description 7
- 150000003624 transition metals Chemical class 0.000 claims description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 4
- 239000004215 Carbon black (E152) Substances 0.000 claims description 4
- 229910052783 alkali metal Inorganic materials 0.000 claims description 4
- 150000001340 alkali metals Chemical class 0.000 claims description 4
- 229930195733 hydrocarbon Natural products 0.000 claims description 4
- 150000002430 hydrocarbons Chemical class 0.000 claims description 4
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 3
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 3
- 229910021529 ammonia Inorganic materials 0.000 claims description 2
- 229910001508 alkali metal halide Inorganic materials 0.000 claims 1
- 150000008045 alkali metal halides Chemical class 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 description 12
- 239000007789 gas Substances 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 150000004820 halides Chemical class 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000008267 milk Substances 0.000 description 1
- 210000004080 milk Anatomy 0.000 description 1
- 235000013336 milk Nutrition 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003746 solid phase reaction Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
Landscapes
- Catalysts (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Description
【発明の詳細な説明】
産業上の利用分野
この発明は、針状晶窒化ケイ素の製造方法に関
するものである。
従来の技術
例えば、特許第838421号は、弗化物、酸性弗化
物または珪弗化物を付着した非晶質シリカ粉末に
炭素質物質の粉末を混合し、窒素雰囲気中で1300
〜1600℃に焼成することを特徴とする針状晶窒化
ケイ素の製造方法について開示している。
発明が解決しようとする問題点
前述の方法を含め従来の針状晶窒化ケイ素の製
造方法は、シリカ粉末と炭素粉末の混合物を反応
させる固相−固相反応である。このため、シリカ
とカーボンの混合が不十分になり易い。混合が不
十分な場合、反応が不均一になる。反応が不均一
になると、生成するウイスカーの径が不揃いにな
つたり、粒子状の窒化ケイ素が生成し易くなる。
発明の目的
前述の問題点に鑑み本発明は、収率がよく、粒
状の窒化ケイ素を含まず、しかも径のそろつた針
状晶窒化ケイ素を得ることのできる針状晶窒化ケ
イ素の製造方法を提供することを目的としてい
る。
問題点を解決するための手段
本発明の針状晶窒化ケイ素の製造方法において
は、シリカ粉末あるいは、シリカ粉末に遷移金
属、アルカリ金属、アルカリ土類金属、遷移金属
のハロゲン化物、アルカリ金属のハロゲン化物、
または遷移金属のハロゲン化物の６種のうちから
選んだ少なくとも１種を加えた混合物を出発物質
とする。前記混合物の混合比は、シリカ粉末１モ
ル部に対して前述の６種のうちから選んだ少なく
とも１種は0.001〜1.0モル部である。アンモニア
（NH3）ガスと炭化水素（CmHn）ガスとの混合
ガスの混合比を、CmHnをCH4に換算して
NH3／CH4＝0.5〜2000（体積比）にし、かつ800
℃〜1650℃の温度でシリカ粉末と必要に応じて前
記混合物を加熱して窒化ケイ素を針状にすること
によつて針状晶窒化ケイ素を製造する。
針状晶窒化ケイ素は基本的にはの反応で作ら
れる。
3SiO2＋4NH3
→Si3N4＋6H2Ｏ …
SiO2にFe，Ni，Co等の遷移金属、アルカリ金
属、アルカリ土類金属あるいはこれらのハロゲン
化物を添加することにより、添加しない場合に比
べ、より速く反応を進行させ、かつ生成するSi3
N4の形態を針状晶（ウイスカー）とすることが
できる。これらの添加物の添加量が、SiO2１モ
ル部に対し、0.001モル部より少ないと、触媒と
しての効果が得られない。また、１モル部を超え
ると、原料シリカと化合し、ガラス相を生成し、
反応速度を著しく低下させる。
の反応により生成するH2Ｏの分圧を下げ、
の反応をよりすみやかに進行させるために炭化
水素（CmHn）ガスを用いる（第式参照）。
mH2Ｏ＋CmHn
→mCO＋（ｍ＋ｎ／２）H2 …
このように、反応ガスとしては、NH3と
CmHnの混合ガスを用いる。そして混合ガスの流
速を0.1〜10mm／秒に設定する。NH3とCmHnの
混合割合について述べると、CmHnをCH4に換算
して、NH3／CH4が0.5（体積比）より小さい場合
には、NH3の分圧が低くなりすぎて反応の進行
が遅くなりがちである。NH3／CH4＞2000の場
合には、CmHnを添加する効果がほとんどなくな
る。
次に反応温度について述べる。反応温度が800
℃より低温では実質的に反応が進行しない。1650
℃より高温ではSiCが生成し、得られる針状晶窒
化ケイ素の純度が低下する。
実施例
実施例 １
平均粒径0.02μmのシリカ粉末３ｇを窒化ケイ
素製ルツボに入れ、さらにそのルツボを黒鉛製ル
ツボに入れて、高周波誘導炉中にセツトした。こ
のルツボをNH3とC3H8との混合気流（たとえば
１mm／秒）において、1400℃で４時間保持し、針
状晶窒化ケイ素を得た。得られた生成物について
Ｘ線回析およびSEMによる形状観察を行つた。
その結果を表１に示す。
平均粒径0.02μmのシリカ粉末３ｇにNaClを対
シリカモル比で0.05加えた。これにアセトンを加
えてメノウ乳バチで混合し、その後乾燥した。得
られた混合物を実施例１と同様の方法で針状晶窒
化ケイ素を製造した。ただし、加熱温度は1450℃
である（実施例２）。
実施例３では、NaFを対シリカモル比で0.5加
え、実施例１と同様の方法で針状晶窒化ケイ素を
製造した。
同様に表１に示す条件で実施例４〜６において
針状晶窒化ケイ素を製造し、形状観察を行つた。
また、表１に示す条件で比較例１〜４において
針状晶窒化ケイ素の製造を試み、形状観察を行つ
た。
この結果、実施例１〜６によれば、長さ及び径
の比較的そろつた針状晶窒化ケイ素が収率よく得
られることが明らかになつた。
また、窒化ケイ素製ボートにシリカ粉末を入
れ、そのボートをアルミナ炉芯管中にセツトし
て、窒化ケイ素の針状化を図つてもよい。
発明の結果
本発明の針状晶窒化ケイ素の製造方法によれ
ば、収率よく短時間で、粒状の窒化ケイ素を含ま
ず、比較的径のそろつた針状晶窒化ケイ素を得る
ことができる。
【表】DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for producing acicular silicon nitride. Conventional technology For example, in Japanese Patent No. 838421, carbonaceous material powder is mixed with amorphous silica powder to which fluoride, acidic fluoride, or silicofluoride is attached, and
Discloses a method for producing acicular silicon nitride characterized by firing at a temperature of ~1600°C. Problems to be Solved by the Invention Conventional methods for producing acicular silicon nitride, including the methods described above, are solid phase-solid phase reactions in which a mixture of silica powder and carbon powder is reacted. For this reason, silica and carbon tend to be insufficiently mixed. If mixing is insufficient, the reaction will be non-uniform. If the reaction becomes non-uniform, the diameters of the generated whiskers will be uneven, and particulate silicon nitride will be more likely to be generated. Purpose of the Invention In view of the above-mentioned problems, the present invention provides a method for producing acicular silicon nitride that has a good yield, does not contain granular silicon nitride, and can obtain acicular silicon nitride with a uniform diameter. is intended to provide. Means for Solving the Problems In the method for producing acicular silicon nitride of the present invention, silica powder or silica powder contains transition metals, alkali metals, alkaline earth metals, halides of transition metals, halides of alkali metals, etc. monster,
Alternatively, a mixture containing at least one selected from six types of transition metal halides is used as a starting material. The mixing ratio of the mixture is 0.001 to 1.0 parts by mole of at least one selected from the above six types to 1 part by mole of silica powder. The mixture ratio of ammonia (NH 3 ) gas and hydrocarbon (CmHn) gas is calculated by converting CmHn to CH 4 .
NH 3 /CH 4 = 0.5 to 2000 (volume ratio), and 800
Acicular silicon nitride is produced by heating the mixture optionally with silica powder at a temperature of 1650°C to 1650°C to make the silicon nitride into needles. Acicular silicon nitride is basically produced by the reaction of . 3SiO 2 +4NH 3 →Si 3 N 4 +6H 2 O... By adding transition metals such as Fe, Ni, Co, alkali metals, alkaline earth metals, or halides of these to SiO 2 , compared to the case without addition, Si 3 that allows the reaction to proceed faster and is produced
The form of N 4 can be in the form of needles (whiskers). If the amount of these additives added is less than 0.001 mol part per 1 mol part of SiO 2 , no catalytic effect can be obtained. In addition, if it exceeds 1 mole part, it will combine with the raw material silica and produce a glass phase.
Significantly slows down the reaction rate. Lower the partial pressure of H 2 O produced by the reaction of
Hydrocarbon (CmHn) gas is used to make the reaction proceed more quickly (see formula 1). mH 2 O + CmHn → mCO + (m + n / 2) H 2 ... In this way, the reaction gases are NH 3 and
A mixed gas of CmHn is used. Then, the flow rate of the mixed gas is set to 0.1 to 10 mm/sec. Regarding the mixing ratio of NH 3 and CmHn, if CmHn is converted to CH 4 and NH 3 /CH 4 is less than 0.5 (volume ratio), the partial pressure of NH 3 will be too low and the reaction will not proceed. tends to be delayed. When NH 3 /CH 4 >2000, the effect of adding CmHn is almost lost. Next, the reaction temperature will be described. Reaction temperature is 800℃
The reaction does not substantially proceed at temperatures lower than ℃. 1650
At temperatures higher than ℃, SiC is generated and the purity of the obtained acicular silicon nitride decreases. Examples Example 1 3 g of silica powder with an average particle size of 0.02 μm was placed in a silicon nitride crucible, and the crucible was further placed in a graphite crucible, which was then set in a high frequency induction furnace. This crucible was maintained at 1400° C. for 4 hours in a mixed gas flow of NH 3 and C 3 H 8 (for example, 1 mm/sec) to obtain acicular silicon nitride. The shape of the obtained product was observed by X-ray diffraction and SEM.
The results are shown in Table 1. NaCl was added to 3 g of silica powder with an average particle size of 0.02 μm at a molar ratio of 0.05 to silica. Acetone was added to this, mixed with an agate milk drum, and then dried. Acicular silicon nitride was produced from the resulting mixture in the same manner as in Example 1. However, the heating temperature is 1450℃
(Example 2). In Example 3, acicular silicon nitride was produced in the same manner as in Example 1 except that NaF was added at a molar ratio of 0.5 to silica. Similarly, acicular silicon nitride was produced in Examples 4 to 6 under the conditions shown in Table 1, and the shapes were observed. Further, production of acicular silicon nitride was attempted in Comparative Examples 1 to 4 under the conditions shown in Table 1, and the shapes were observed. As a result, it was revealed that according to Examples 1 to 6, acicular silicon nitride having relatively uniform length and diameter could be obtained in good yield. Alternatively, silica powder may be placed in a silicon nitride boat, and the boat may be set in an alumina furnace tube to form the silicon nitride into an acicular shape. Results of the Invention According to the method for producing acicular silicon nitride of the present invention, acicular silicon nitride containing no particulate silicon nitride and having a relatively uniform diameter can be obtained in a high yield and in a short time. 【table】
Claims (1)
（CmHn）ガスの混合ガスの混合比が炭化水素
（CmHn）をCH4に換算してCH4に対するNH3の
体積比（NH3／CH4）が0.5〜2000になるように
調整し、該混合ガスの流速を0.1〜10mm／秒とし、
かつ800℃〜1650℃の温度でシリカ粉末に遷移金
属、アルカリ金属、アルカリ土類金属、遷移金属
のハロゲン化物、アルカリ金属のハロゲン化物、
または遷移金属のハロゲン化物の６種のうちから
選んだ少なくとも１種を、該シリカ粉末１モル部
に対して0.001〜1.0モル加えた混合物を加熱して
窒化ケイ素を針状にすることを特徴とする針状晶
窒化ケイ素の製造方法。1 The mixture ratio of ammonia (NH 3 ) gas and hydrocarbon (CmHn) gas is 0.5 when the hydrocarbon (CmHn) is converted to CH 4 and the volume ratio of NH 3 to CH 4 (NH 3 /CH 4 ) is 0.5. ~2000, and the flow rate of the mixed gas was set to 0.1 to 10 mm/sec.
and transition metals, alkali metals, alkaline earth metals, transition metal halides, alkali metal halides,
Alternatively, a mixture of 0.001 to 1.0 mol of at least one selected from six types of transition metal halides per 1 mol part of the silica powder is heated to make the silicon nitride into needle-like shapes. A method for producing acicular silicon nitride.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10768488A JPH01278405A (en) | 1988-05-02 | 1988-05-02 | Production of acicular silicon nitride |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10768488A JPH01278405A (en) | 1988-05-02 | 1988-05-02 | Production of acicular silicon nitride |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01278405A JPH01278405A (en) | 1989-11-08 |
| JPH0511047B2 true JPH0511047B2 (en) | 1993-02-12 |
Family
ID=14465348
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10768488A Granted JPH01278405A (en) | 1988-05-02 | 1988-05-02 | Production of acicular silicon nitride |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01278405A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5814290A (en) * | 1995-07-24 | 1998-09-29 | Hyperion Catalysis International | Silicon nitride nanowhiskers and method of making same |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5673603A (en) * | 1979-11-14 | 1981-06-18 | Toshiba Corp | Manufacture of silicon nitride |
| JPS63162516A (en) * | 1986-12-26 | 1988-07-06 | Toshiba Ceramics Co Ltd | Production of silicon nitride |
-
1988
- 1988-05-02 JP JP10768488A patent/JPH01278405A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5673603A (en) * | 1979-11-14 | 1981-06-18 | Toshiba Corp | Manufacture of silicon nitride |
| JPS63162516A (en) * | 1986-12-26 | 1988-07-06 | Toshiba Ceramics Co Ltd | Production of silicon nitride |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01278405A (en) | 1989-11-08 |
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