JPS6037078B2 - Method for manufacturing silicon nitride whiskers - Google Patents

Description

【発明の詳細な説明】 この発明は、籾殻その他の炭素及び珪素を含む薄肉多孔
性原料を用いて窒化珪素ウイスカーを工業規模で製造す
る方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing silicon nitride whiskers on an industrial scale using rice husk or other thin porous raw materials containing carbon and silicon.

繊維状の単結晶であるウィスカーは、同じ物質の塊状結
晶体や多結晶体に較べて格段と機械的強度が高いので、
他の物質に混入して機械的強度が高い複合材料を得るた
めの強化物質として注目されており、現在では金属、金
属酸化物、金属炭化物、金属ほう化物などのウイスカー
が市場に現われている。Whiskers, which are fibrous single crystals, have much higher mechanical strength than bulk crystals or polycrystals of the same material.
Whiskers are attracting attention as reinforcing substances that can be mixed with other substances to obtain composite materials with high mechanical strength, and whiskers such as metals, metal oxides, metal carbides, and metal borides are now appearing on the market.

一方、窒化珪素を用いたセラミック材料は、熱衝撃抵抗
が極めて大きく、高温下での耐食性、絶縁性、耐摩耗性
が優れているため、高級高温材料として、航空、宇宙関
連技術を始めとする広い分野で利用が進みつ）ある。On the other hand, ceramic materials using silicon nitride have extremely high thermal shock resistance and excellent corrosion resistance, insulation properties, and wear resistance at high temperatures, so they are used as high-grade high-temperature materials for applications such as aviation and space-related technologies. Its use is progressing in a wide range of fields.

窒化珪素は、セラミック状態ですらこのような優れた性
質を有しているから、そのウィスカーが前述のような従
釆の各種物質のウィスカーに較べて優れたものであるこ
とは明白であるが、従来は実験室規模で製造、研究が行
われていたにとどまり、その収率は極めて低く、工業的
用途に利用できなかった。従来から試みられている窒化
珪素ゥィスカーの製造法は、珪素を含有する原料を破砕
または造粒して炉に装填し、これを加熱して珪素を含む
蒸気を発生させ、この蒸気に窒素ガスを反応させてウイ
スカーを成長させる気相法が主流をなしている。Since silicon nitride has such excellent properties even in its ceramic state, it is clear that its whiskers are superior to the whiskers of various related materials as mentioned above. Until now, production and research had only been carried out on a laboratory scale, and the yield was extremely low, making it impossible to use it for industrial purposes. The manufacturing method of silicon nitride whiskers that has been attempted in the past involves crushing or granulating silicon-containing raw materials, loading them into a furnace, heating them to generate silicon-containing steam, and adding nitrogen gas to this steam. The vapor phase method, which grows whiskers through reaction, is the mainstream.

その場合、加熱された原料粉または原料べレットに直接
窒素ガスを接触させると、原料粉末粒子間や原料べレツ
ト表面に窒化珪素が生成し、粉末内部やべレット内部か
らの珪素蒸気の蒸発を妨げる。よって、通常は加熱され
た原料内を不活性のキャリャーガスを通過させて珪素を
含む蒸気を搬出させ、原料から離れた空間で窒素ガスを
反応させ（特公昭４１−１７９６７号公報参照）たり、
窒素ガスに塩素ガスや水素ガスを加えた混合ガスを原料
内を通過させて、原料から離れた空間で搬出された珪素
成分と混合ガス中の窒素とを反応させ（特公階４９一２
７７５５号公報参照）ており、その場合は炉の天井や側
壁にウィスカーが成長する。このように炉内の原料から
離れた位置にウィスカーを生成させる場合、原料に用い
た珪素成分が峯化珪素ゥィスカーに変換される効率は、
例えば０．２〜１１．３％（椿公昭５０−４４８ぴ号公
報参照）というように極めて低いものである。この発明
は、原料中の珪素成分の袷んどすべてを窒化珪素に変換
でき、しかも生成した窒化珪素の半分以上がウィスカー
を形成している極めて高効率のウィスカー製造方法を実
現することを目的とする。In that case, when nitrogen gas is brought into direct contact with the heated raw material powder or raw material pellet, silicon nitride is generated between the raw material powder particles and on the surface of the raw material pellet, preventing the evaporation of silicon vapor from inside the powder or pellet. hinder. Therefore, usually an inert carrier gas is passed through the heated raw material to carry out the silicon-containing vapor, and nitrogen gas is reacted in a space away from the raw material (see Japanese Patent Publication No. 17967/1983).
A mixed gas containing nitrogen gas, chlorine gas, and hydrogen gas is passed through the raw material, and the silicon component carried out in a space away from the raw material reacts with the nitrogen in the mixed gas (Special Public Floor 49-2).
(Refer to Publication No. 7755), in which case whiskers grow on the ceiling and side walls of the furnace. In this way, when whiskers are generated at a location away from the raw material in the furnace, the efficiency with which the silicon component used in the raw material is converted into phosphorized silicon whiskers is:
For example, it is extremely low, 0.2 to 11.3% (see Tsubaki Publication No. 50-448). The purpose of this invention is to realize an extremely efficient whisker manufacturing method in which all of the silicon components in the raw material can be converted into silicon nitride, and more than half of the produced silicon nitride forms whiskers. do.

この発明において、珪素成分の供給源料としては、炭素
及び珪素を含有する薄片状、短管状、薄板状、からみ合
った糸状などのものを用い、相互間に十分な空隙を保有
させて炉に装填する。In this invention, materials containing carbon and silicon in the form of flakes, short tubes, thin plates, entangled threads, etc. are used as the source material for the silicon component, and the materials are kept in the furnace with sufficient voids between them. Load.

即ち、珪素成分の供給原料は、粉砕したり造粒したりし
ない。好ましい原料としては、米国特許第３８５５３９
５号や特開昭５２一７９ｙ号の発明でも用いられている
籾殻が挙げられる。That is, the silicon component feedstock is not crushed or granulated. Preferred raw materials include U.S. Patent No. 385,539.
For example, rice husks are used in the inventions of No. 5 and JP-A-52-79Y.

籾殻は、稲作農業で多重に創生するが、特に頭着な用途
に供されていない。しかし、成分として有機物の他にＳ
ｊ０２が１３〜２２％、Ｍｇ。が。・〇２〜〇・〇５％
、Ｃａ。が。・１０〜〇・１５％、Ｋ２０が０．３〜０
．４％、Ｐ２０５が０．０５〜０．１０％含まれており
、これを空気遮断して蝦競すると、その重量の約６０％
が飛散し、炭素分と珪酸分との比率は７：３〜５：５と
なる。このうちの炭素分は、窒化工程中籾殻が形状を維
持するのに貢献し、珪酸分がゥィスカーの生成に使われ
る。残余の不純物のうち、Ｋ２０及びＰ２０５は蝦競及
び窒化工程中に樽散し、Ｍｇ○及びＣａ０は後処理によ
って除去することができる。高純度を要する場合には、
例えば、櫨紙のような高純度のセルローズ質に、珪酸或
いはシリコン樹脂を合浸し乾燥させたものを、相互間に
十分な空隙が出来るように成形し、原料として用いると
よい。Although rice husks are produced in multiple forms during rice farming, they are not used for any particular purpose. However, in addition to organic substances, S
j02 13-22%, Mg. but.・〇2〜〇・〇5%
, Ca. but.・10~〇・15%, K20 is 0.3~0
．． 4%, P205 is 0.05-0.10%, and when it is air-blocked and competed with shrimp, it weighs about 60% of its weight.
is scattered, and the ratio of carbon content to silicic acid content becomes 7:3 to 5:5. The carbon content helps the rice husks maintain their shape during the nitriding process, and the silicic acid content is used to generate whiskers. Among the remaining impurities, K20 and P205 can be dispersed during the molding and nitriding steps, and Mg○ and Ca0 can be removed by post-treatment. If high purity is required,
For example, it is preferable to use a material obtained by soaking silicic acid or silicone resin in high-purity cellulosic material such as oak paper and drying it, forming the material so that there are sufficient gaps between them and using the material as a raw material.

この発明における原料の炉への装填は、原料が薄板乃至
は薄片の形状を維持し、相互間に十分な空隙を維持させ
ることが必要である。When loading the raw material into the furnace in this invention, it is necessary that the raw material maintains the shape of a thin plate or flake, and that sufficient voids are maintained between the raw materials.

前記米国特許第３８５５３９５号の発明は、籾殻を原料
としてはいるが、蝦暁後にべレット状に造粒して炉へ装
填し、また、特開８召５２一７９９号の発明では暇焼し
た籾殻を細かく粉砕して炉へ装填しているのに対し、こ
の発明において籾殻を原料に用いる場合は、籾殻の形状
を可及的に損わないようにして炉へ装填するのである。
原料の蝦焼は、炉へ装填する前及び装填した後の何れで
もよく、装填後の蝦焼は、空気遮断して炉体を加熱する
か、或いは非酸化性の高温ガスを原料相互間の空隙を流
れるように炉内へ供給すればよい。The invention of U.S. Pat. No. 3,855,395 uses rice husks as a raw material, but after drying, it is granulated into pellets and loaded into a furnace, and the invention of JP-A-8-52-799 uses rice husks as a raw material. Whereas rice husks are finely ground and loaded into a furnace, when rice husks are used as a raw material in the present invention, they are loaded into a furnace in a manner that does not damage the shape of the rice husks as much as possible.
The raw materials can be roasted either before or after loading them into the furnace. For roasting after loading, the furnace body is heated with air shut off, or non-oxidizing high-temperature gas is passed between the raw materials. What is necessary is to supply it into the furnace so that it flows through the gap.

この高温ガスとして窒素を用いれば、そのま）次の窒化
工程へ移行することができる。窒化工程は、炉内を１３
００〜１４５０００、好ましくは１３８０〜１４００ｑ
ｏに維持し窒素ガスを流通させる。窒素ガスの流量、流
速及び温度は、炉の形状や原料の量によって異なるが、
ガスによって原料が著しく冷却されないことが必要であ
る。反応の所要時間は１〜５時間、好ましくは４〜５時
間である。窒化工程を終えると、窒化珪素ウィスカーが
炭化した原料の相互間隙内に線状乃至は羽毛状に成長し
ている。勿論、従来の製法と同様に炉の天井や側壁にも
ウィスカーが成長するが、原料間に成長する量の方が圧
倒的に多い。そして、窒素工程が十分な時間行なわれる
と、原料中の珪酸分の殆んど全量が窒化珪素に変換され
、窒化珪素の粉体とウィスカーとの比率は４の対６の前
後の極めて高いものになる。炉から取出した原料を水と
鉱油の混在液中に入れ、機械的、ヱアレーション、超音
波などによって蝿拝してほぐし、静直すると、ウィスカ
ーが水中に、原料が油中に分離する。If nitrogen is used as the high-temperature gas, it is possible to proceed directly to the next nitriding step. In the nitriding process, the inside of the furnace is
00-145000, preferably 1380-1400q
o and nitrogen gas is passed through. The flow rate, flow rate, and temperature of nitrogen gas vary depending on the shape of the furnace and the amount of raw materials, but
It is necessary that the gas does not significantly cool the feedstock. The time required for the reaction is 1 to 5 hours, preferably 4 to 5 hours. After the nitriding process, silicon nitride whiskers grow in the form of lines or feathers within the interstices of the carbonized raw material. Of course, whiskers grow on the ceiling and side walls of the furnace just like in conventional manufacturing methods, but the amount that grows between the raw materials is overwhelmingly greater. When the nitrogen process is carried out for a sufficient period of time, almost all of the silicic acid content in the raw material is converted to silicon nitride, and the ratio of silicon nitride powder to whiskers is extremely high, around 4:6. become. The raw material taken out of the furnace is placed in a mixture of water and mineral oil, and is loosened by mechanical, aeration, or ultrasonic waves, and when it settles down, the whiskers are separated into water and the raw material is separated into oil.

水中で横集したウィスカーは、浮遊選鉱技術、酸洗い、
水洗等適宜の精選を行う。なお、油中で捕集した原料は
、６００〜１２０ぴ０の酸化雰囲気中で焼成すると、窒
化珪素粉が残るので、高温セラミック原料などとして利
用する。また、炉から取出した原料をそのまま焼成する
と、ウィスカー及び窒化珪素粉の混合物が得られるが、
これを高温セラミック原料に用いれば、機械的強度が高
い高温材料が得られる。この発明を工業的に実施する際
の窒化炉としては、図示のような構造のものが適当であ
る。１は耐火材料で作られた炉体で、両端に挿入口２及
び取出口３を有し、外面は気密な鋼板（図示せず）によ
って覆われている。Whiskers collected horizontally in water are processed using flotation technology, pickling,
Perform appropriate selection such as washing with water. Note that when the raw material collected in oil is fired in an oxidizing atmosphere of 600 to 120 mm, silicon nitride powder remains, so it is used as a raw material for high-temperature ceramics. Also, if the raw material taken out of the furnace is fired as it is, a mixture of whiskers and silicon nitride powder will be obtained.
If this is used as a raw material for high-temperature ceramics, a high-temperature material with high mechanical strength can be obtained. As a nitriding furnace for industrially implementing this invention, one having a structure as shown in the drawing is suitable. Reference numeral 1 denotes a furnace body made of a refractory material, which has an insertion port 2 and an output port 3 at both ends, and its outer surface is covered with an airtight steel plate (not shown).

挿入口２及び取出口３には、それぞれ開閉可能な扉４及
び５が設けられる。炉体１内は、予熱帯６と反応帯７と
冷却帯８とに区分される。各帯域６，７，８にはそれぞ
れカーボントレー９，１０，１１が収容されており、挿
入口２から新たなトレーを挿入することによって、各ト
レーは隣接帯城へ送られ、冷却帯８にあったトレー１１
は取出口３から外界へ押出される。各トレーは、底に原
料の籾殻１２がこばれ落ちない程度の細孔が無数に穿孔
されている。予熱帯６では、炉体１内に設けた発熱体１
３によって、トレーに収容して挿入された原料を、トレ
ーと共に所定時間後に窒化反応温度近辺にまで徐々に昇
温させる。この時、酸化雰囲気になって原料が燃焼する
のを防ぐために、反応帯７から管路１４を経て送られて
来る窒素ガスにより、非酸化雰囲気に保たれる。この窒
素ガスは排気管１５から外界へ排出される。反応帯７内
は、炉体内に設けた発熱体１６により珪素の窒化に通し
た１３８０〜１４００ｑ Ｃに維持される。The insertion port 2 and the removal port 3 are provided with doors 4 and 5 that can be opened and closed, respectively. The inside of the furnace body 1 is divided into a preheating zone 6, a reaction zone 7, and a cooling zone 8. Carbon trays 9, 10, 11 are accommodated in each zone 6, 7, 8, respectively, and by inserting a new tray from the insertion port 2, each tray is sent to the adjacent zone and is placed in the cooling zone 8. There was a tray 11
is pushed out from the outlet 3 to the outside world. Each tray has a large number of pores perforated in its bottom to prevent the raw material rice husks 12 from falling out. In the preheating zone 6, the heating element 1 provided in the furnace body 1
3, the temperature of the raw material contained in the tray and inserted into the tray is gradually raised to around the nitriding reaction temperature after a predetermined period of time. At this time, in order to prevent the raw materials from burning due to an oxidizing atmosphere, a non-oxidizing atmosphere is maintained by nitrogen gas sent from the reaction zone 7 through the pipe 14. This nitrogen gas is exhausted from the exhaust pipe 15 to the outside world. The inside of the reaction zone 7 is maintained at 1380 to 1400 q C, which is sufficient for nitriding silicon, by a heating element 16 provided in the furnace body.

窒素ガスは炉底に設けた送気管１７から送入され、炉底
に敷いたカーボンベレツト１８の隙間を通過する際に十
分加熱され、トレー１０内へその底の紬孔から入り、原
料１２の間隙を通ってその上部空間に抜ける。１９は必
要に応じ反応帯７の上部空間に窒素ガスを補給する送気
管である。Nitrogen gas is introduced from an air supply pipe 17 installed at the bottom of the furnace, is heated sufficiently as it passes through the gap between carbon pellets 18 laid at the bottom of the furnace, enters the tray 10 through the pongee hole at the bottom, and is heated to the raw material 12. It passes through the gap in the gap and into the space above it. Reference numeral 19 denotes an air supply pipe that supplies nitrogen gas to the upper space of the reaction zone 7 as required.

前述のように、この上部空間の天井や側壁にもウィスカ
ーが成長するので、随時これを捕集するために、反応帯
７の天井は開閉可能な蓋２０で構成する。冷却帯８では
、窒化反応を終った原料をトレーと共に徐冷する。As mentioned above, since whiskers grow on the ceiling and side walls of this upper space, the ceiling of the reaction zone 7 is constructed with an openable and closable lid 20 in order to collect whiskers at any time. In the cooling zone 8, the raw material that has undergone the nitriding reaction is gradually cooled together with the tray.

そのために、必要に応じ炉体１内に発熱体（図示せず）
を設けることもある。上述の窒化炉は、４〜５時間ごと
に新たな原料を収容したトレーを挿入口２から押込み、
かつ反応を終った原料を収容しているトレーを取出口３
から押出させる。工業的窒化炉としては、図示のものの
他に、一端からスクリューフィダにより原料を連続的ま
たは間歌的に挿入して、炉内を移動中に窒化させ、他端
から反応を終った原料を排出させる縦型のものを使用す
ることもでき、その場合にはトレーを使用しなくてよい
。For this purpose, a heating element (not shown) is installed in the furnace body 1 as necessary.
may be provided. In the above-mentioned nitriding furnace, a tray containing new raw materials is pushed in through the insertion port 2 every 4 to 5 hours.
And the tray containing the reacted raw materials is removed from the outlet 3.
extrude from In addition to the one shown in the figure, other industrial nitriding furnaces include one in which raw materials are continuously or intermittent fed into one end using a screw feeder, nitrided while moving through the furnace, and the raw materials that have completed the reaction are fed into the other end. It is also possible to use a vertical type with discharge, in which case there is no need to use a tray.

次に、この発明の実施例を説明する。Next, embodiments of the invention will be described.

実施例 １ 空気遮断して蝦競した籾殻１００夕を、下部に多数の孔
を開けた黒鉛製の容器に入れ、蓋をせずにアルミナ製マ
ッフル炉に黒鉛のべレットを５狐程充填した上に置き窒
素ガスを０．５夕／分で炉下部より上部に流して昇温し
、１４０ぴ０に達したとき窒素ガス流量を４夕／分とし
て４時間保持した後、窒素ガス流量を０．５そ／分とし
て１０００ｏｏ迄降温し、この後ガス送入を止めて密閉
冷却した。Example 1 100 tons of rice husks that had been harvested with air cut off were placed in a graphite container with many holes in the bottom, and about 5 graphite pellets were filled into an alumina muffle furnace without a lid. The temperature was raised by flowing nitrogen gas from the bottom of the furnace to the top at a rate of 0.5 m/min, and when the temperature reached 140 pm, the nitrogen gas flow rate was set to 4 m/min and the temperature was maintained for 4 hours. The temperature was lowered to 1000 oo at a rate of 0.5 so/min, after which the gas supply was stopped and the reactor was cooled in a hermetically sealed manner.

容器内焼成物を灯油：水（水道水）、３：７の混合液に
入れ、３び分蝿梓後静直し、油側分離物は酸化雰囲気中
で８００ｑ０２時間焼成し、灰白色の粉体１２．２夕を
得た、水側分離物は脱水乾燥して１５．４夕のゥィスカ
ーを得た。ウィスカーは径０．３〜１．０仏の、長さ１
００〜２００り肌でＸ線回折でゥィスカー粉体ともＱ一
ＳらＮ４であることが認められた。そして、蟹光Ｘ線に
よる不純物の定量値は、ウィスカーはＣａが０．１０％
、Ｍｇが０．０４％、Ｆｅが１．５６％であり、粉体は
Ｃａが０．１２％、Ｍ教主０．０６％、Ｆｅが１．７５
％であった。実施例 ２ 空気遮断して蝦競した籾殻１００夕を、塩酸で１時間煮
沸し、温湯で洗総して乾燥し、これを実施例１と同じ手
法で窒化し生成物を分離した。The fired product in the container was placed in a 3:7 mixture of kerosene and water (tap water), and allowed to settle after 3 minutes.The oil-side separated product was fired in an oxidizing atmosphere for 800q02 hours to form a grayish white powder. The water-side separated product was dehydrated and dried to obtain 15.4 whiskers. The whisker has a diameter of 0.3 to 1.0 mm and a length of 1
The whisker powder was confirmed to be Q-S et N4 by X-ray diffraction at 0.00 to 200. The quantitative value of impurities using crab light X-rays shows that the whisker contains 0.10% Ca.
, Mg is 0.04%, Fe is 1.56%, and the powder contains Ca 0.12%, M Kyoshu 0.06%, and Fe 1.75%.
%Met. Example 2 100 tons of rice husks, which had been washed with air shut off, were boiled in hydrochloric acid for 1 hour, washed thoroughly with warm water, dried, and nitrided in the same manner as in Example 1 to separate the product.

鞍光Ｘ線による不純物の定量値は、ウィスカーはＣａが
０．０２、Ｍｇが痕跡程度、Ｆｅが０．４２％であり、
粉体はＣａが０．０３％、Ｍｇが０．０１％、Ｆｅが０
．５３％と、大幅に純度が向上した。実施例 ３ 生の籾殻を塩酸で１時間煮沸し、温湯で洗練後乾燥して
蝦焼した籾殻１００夕を、実施例１と同じ手法で窒化し
、生成物を分離した。The quantitative values of impurities by saddle light X-rays are that the whisker contains 0.02% Ca, a trace amount of Mg, and 0.42% Fe.
The powder contains 0.03% Ca, 0.01% Mg, and 0 Fe.
．． The purity was significantly improved to 53%. Example 3 100 pieces of raw rice husk were boiled in hydrochloric acid for 1 hour, polished with warm water, dried and roasted, and then nitrided in the same manner as in Example 1 to separate the product.

蟹光Ｘ線による不純物の定量値は、Ｃａが０．０３％、
Ｍｇが痕跡程度、Ｆｅが０．６１％であり、粉体はＣａ
が０．０４％、Ｍｇが０．０１％、Ｆｅが０．７７％で
あった。実施例 ４実施例１と同じ方法で得た窒化珪素
ゥィスカーを５夕、亀融Ｃａ安定化ジルコニア、３２５
メッシュ通過体４０夕と混合し、１００ｋ９／ｃ流の圧
力でＣＭＣをバインダーとしてプレス成形した。Quantitative values of impurities using crab light X-rays are 0.03% Ca,
The powder contains traces of Mg, 0.61% Fe, and Ca.
was 0.04%, Mg was 0.01%, and Fe was 0.77%. Example 4 Silicon nitride whiskers obtained in the same manner as in Example 1 were treated with Kamemel Ca-stabilized zirconia, 325
It was mixed with 40 pieces of mesh passing material and press-molded at a pressure of 100k9/c using CMC as a binder.

１７００００１時間非酸化雰囲気で焼成した結果、ゥイ
スカ−を配合していない焼成体の圧縮強度が１８６ｋｇ
／のであるのに対し、ウイスカー配合体は２７５ｋ９／
鮒を強度の増大が認められた。As a result of firing in a non-oxidizing atmosphere for 1,700,001 hours, the compressive strength of the fired product without whiskers was 186 kg.
/, while the whisker compound is 275k9/
An increase in the strength of crucian carp was observed.

実施例 ５実施例１と同じ方法で得た窒化珪素ゥィスカ
ー５０夕、露融マグネシア３２５メッシュ通過粉砕物２
００夕を混合し、メチルセルローズノゞィンダーを加え
て４柳ぐの円筒を押し成形し、１６００ｑｏ非酸化雰囲
気で焼成した。Example 5 Silicon nitride whiskers obtained in the same manner as in Example 1 (50 g), dew-melted magnesia (325 mesh), pulverized product 2
The mixture was mixed with 1,000 liters of water, methylcellulose powder was added, and a 4-year cylinder was pressed and fired in a 1,600 qo non-oxidizing atmosphere.

ゥィスカー配合なしの焼成体との比較はつぎのようであ
る。曲げ強度 電気絶縁抵抗（１０００ｑｏ）Ｍｇ。A comparison with a fired body without whisker blending is as follows. Bending strength Electrical insulation resistance (1000qo) Mg.

２７２・５×９′Ｃ鰭 １‐５×１０７Ｑ
ＣのＭｇ○十ウイスカー３６５．６ｋｇ／ｃ的 １．
３６×１０７Ｑｃの実施例 ６実施例１と同じ方法で窒
化したものを、油水温合液による分離をせずにそのま）
８００ｏ０２時間の酸化雰囲気で焼成して炭素分だけを
除き、乳鉢で軽く粉砕し４０メッシュ節を通して、窒化
珪素ウィスカーと窒化珪素粉体との混合物を得、これに
２．５％のＭｇ○、０．５％のＹ２０３を添加し、ポリ
ビニールアルコールをバインダーとして半乾式で５００
ｋ９ノｃ椎の圧力でプレス成形した。272.5×9′C fin 1-5×107Q
Mg○1 whisker of C 365.6kg/c 1.
Example 6 of 36×107Qc (Nitrided in the same manner as in Example 1, without separation by oil/water hot mixture)
The carbon content was removed by firing in an oxidizing atmosphere at 800°C for 2 hours, and the mixture was lightly crushed in a mortar and passed through a 40-mesh node to obtain a mixture of silicon nitride whiskers and silicon nitride powder, which was mixed with 2.5% Mg○, 0 500% in a semi-dry process with the addition of .5% Y203 and polyvinyl alcohol as a binder.
It was press-molded using the pressure of K9 vertebrae.

成形体を窒素雰囲気中で１６５０００、２時間焼成した
ものは、高密度２．２夕／ｃ髭、曲げ強度１１ｋ９／側
であった。Ｘ線回折ではＱ−Ｓｉ３Ｎ４、８一Ｓｉ３Ｎ
４が認められ、破断面の走査電子顕微鏡写真でマトリッ
クスに針状結晶の交ごくした状態が観察された。実施例
７実施例１と同じ原料、同じ焼成方法で窒化したもの
を容器中より取出し、乳鉢で粉砕して、窒化珪素ゥィス
カーと窒化珪素粉体と炭素粉体との混合物を得、これに
フェノール樹脂系のバインダーを加えて２００ｋ９／め
でプレス成形した。The molded product baked in a nitrogen atmosphere at 165,000°C for 2 hours had a high density of 2.2mm/c and a bending strength of 11k9/cm. In X-ray diffraction, Q-Si3N4, 8-Si3N
4 was observed, and a scanning electron micrograph of the fracture surface showed a state in which needle-like crystals were interlaced in the matrix. Example 7 The same raw materials and nitrided material as in Example 1 were taken out of the container and crushed in a mortar to obtain a mixture of silicon nitride whiskers, silicon nitride powder, and carbon powder, and phenol was added to this. A resin binder was added and press molded at 200k9/m.

窒素雰囲気中で１７００ｏ０２時間保持で焼成した結果
、圧縮強度１２７ｋｇ′の、気孔率１７．２％の焼成体
を得た。１００ｏ、２００ｏ、３００ｑｏの温度より水
中に投入する急熱急冷の試験においても亀裂などの損傷
は認められなかつた。As a result of firing at 1700° C. for 2 hours in a nitrogen atmosphere, a fired body with a compressive strength of 127 kg' and a porosity of 17.2% was obtained. No damage such as cracks was observed in tests of rapid heating and cooling in which the product was placed in water at temperatures of 100o, 200o, and 300qo.

実施例 ８ 実施例１と同じ原料、同じ焼成法で窒化したものを容器
より取出し、この籾殻の形態が一部残っているものをそ
のま）材料として、リン酸アルミ系のバインダー、針葉
樹パルプ、ポバールを混合し、標準形シートマシンを用
い、ＪＩＳＰ８２０９ぐルプ試験用手すき紙調整方法に
よって厚みＩＱ帆１８０側ぐの抄造板をつくり、これを
８００℃の酸化雰囲気で焼成した。Example 8 The same raw materials as in Example 1, which were nitrided using the same firing method, were taken out of the container, and the rice husks, with some of the rice husks still remaining, were used as materials, including an aluminum phosphate binder, softwood pulp, A paper board having a thickness of IQ sail 180 was made using a standard sheet machine using a standard sheet machine according to the JISP 8209 group test handmade paper preparation method, and this was fired in an oxidizing atmosphere at 800°C.

焼成物は、高比重０．７、熱伝導率０．狐ｃａｌ／ｍｈ
ｒｑＣ（３００ｑｏ）の耐火断熱板として熱衝撃にもき
わめて強いもので、２００℃の温度差の急熱急冷試験で
異常を認めなかった。実施例 ９ ダンボール様の波型に成形した櫨紙にシリコンワニスを
含浸させ、これを空気遮断で１３８０午○で蝦暁したも
のを原料として用い、実施例１と同様の手法により窒化
し、かつ窒化珪素ウィスカ−及び窒化珪素粉体を分離し
た。The fired product has a high specific gravity of 0.7 and a thermal conductivity of 0. fox cal/mh
As a rqC (300 qo) fireproof heat insulating board, it is extremely resistant to thermal shock, and no abnormality was observed in a rapid heating and cooling test with a temperature difference of 200°C. Example 9 A cardboard-like corrugated paper impregnated with silicone varnish and dried at 1,380 pm in an air-blocking state was used as a raw material, and nitrided in the same manner as in Example 1. Silicon nitride whiskers and silicon nitride powder were separated.

得られたゥィスカ−は径約０．５仏の、長さ８０〜１０
０仏肌で、Ｘ線回折でＱ−Ｓｉ３Ｎ４が主体であった。
また不純物は全く検出されなかった。The obtained whisker has a diameter of about 0.5 mm and a length of 80 to 10 mm.
0 Buddha skin, and X-ray diffraction showed that Q-Si3N4 was the main component.
Moreover, no impurities were detected at all.

【図面の簡単な説明】[Brief explanation of the drawing]

図はこの発明の実施に用いる窒化炉の断面図である。 １・・・・・・炉体、２・・・・・・挿入口、３・・・
・・・取出口、４及び５……扉、９〜１１……カーボン
トレー、１２…・・・原料、１３及び１６・・・・・・
発熱体、１７…・・・窒素ガス送気管。The figure is a sectional view of a nitriding furnace used for carrying out the present invention. 1...Furnace body, 2...Insertion port, 3...
...Outlet, 4 and 5...Door, 9-11...Carbon tray, 12...Raw material, 13 and 16...
Heating element, 17...Nitrogen gas pipe.

Claims (1)

【特許請求の範囲】[Claims] １ 薄肉の珪素を含む原料を、ウイスカーの成長に十分
な空隙を相互間に保持させて炉に装填し、非酸化雰囲気
で１３００℃〜１４５０℃に加熱しながら上記空隙に窒
素ガスを流通させ、上記空隙中に窒化珪素のウイスカー
を成長させることを特徴とする窒化珪素ウイスカーの製
造方法。1. Loading thin silicon-containing raw materials into a furnace while maintaining sufficient voids between them for whisker growth, and flowing nitrogen gas through the voids while heating to 1300° C. to 1450° C. in a non-oxidizing atmosphere. A method for producing silicon nitride whiskers, which comprises growing silicon nitride whiskers in the voids.