JPH09235165A - Production of sintered compact of silicon nitride - Google Patents
Production of sintered compact of silicon nitrideInfo
- Publication number
- JPH09235165A JPH09235165A JP8069222A JP6922296A JPH09235165A JP H09235165 A JPH09235165 A JP H09235165A JP 8069222 A JP8069222 A JP 8069222A JP 6922296 A JP6922296 A JP 6922296A JP H09235165 A JPH09235165 A JP H09235165A
- Authority
- JP
- Japan
- Prior art keywords
- silicon nitride
- mixture
- container
- fired
- weight
- 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.)
- Withdrawn
Links
Landscapes
- Ceramic Products (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、均質な窒化珪素焼
結体の製造方法に関する。TECHNICAL FIELD The present invention relates to a method for producing a homogeneous silicon nitride sintered body.
【０００２】[0002]
【従来の技術】窒化珪素焼結体は、窒化珪素単体での焼
結が極めて困難であることから、焼結助剤としてイット
リア−アルミナ系、マグネシア−アルミナ系などを添加
し、非酸化雰囲気中１７００〜１９００℃の温度で液相
焼結することにより緻密質の焼結体が製造されている。
この際、焼成中の雰囲気や該雰囲気に混入した不純物、
酸素化合物を代表とする窒化珪素粉末に含まれる不純
物、焼結助剤等の影響を受け、窒化珪素以外の反応生成
物の生成、及び／又は窒化珪素の分解も生じ易い。2. Description of the Related Art A silicon nitride sintered body is extremely difficult to sinter with silicon nitride alone. Therefore, yttria-alumina type, magnesia-alumina type, etc. are added as sintering aids in a non-oxidizing atmosphere. A dense sintered body is manufactured by liquid phase sintering at a temperature of 1700 to 1900 ° C.
At this time, the atmosphere during firing and impurities mixed in the atmosphere,
Under the influence of impurities, sintering aids, and the like contained in silicon nitride powder represented by oxygen compounds, reaction products other than silicon nitride and / or silicon nitride are easily decomposed.
【０００３】例えば、高温非酸化性雰囲気下で十分耐性
のある緻密質炭素の坩堝や鞘の類を焼成時の被焼成物収
納容器として用い、窒化珪素の焼結を行うことが一般に
行われている。このような方法に於いて見られる高温で
の分解反応としては、酸化されやすい窒化珪素粉末の表
面に生成したシリカと窒化珪素が反応し、一酸化珪素と
窒素が生じることや、アルミナ系焼結助剤を用いた際に
見られるアルミナと窒化珪素の反応により一酸化珪素と
窒素が生じることなどがある。これらの分解反応は焼結
体表層で起こる為、内部と表面が成分的に異なるものと
なり、その結果焼結体に色ムラが生じる。更に分解反応
が進行すると、焼結体表層の緻密性が低いものとなり、
窒化珪素がシリコン化することがある。色斑の生じた焼
結体は商品価値を損なうばかりではなく、表層部の機械
的特性が劣化したものとなる。For example, it is common practice to sinter silicon nitride by using a crucible or sheath of dense carbon, which has sufficient resistance under a high temperature non-oxidizing atmosphere, as a container for storing a material to be fired during firing. There is. As the decomposition reaction at high temperature observed in such a method, silica generated on the surface of silicon nitride powder which is easily oxidized reacts with silicon nitride to generate silicon monoxide and nitrogen, and alumina-based sintering. There is a case where silicon monoxide and nitrogen are generated due to a reaction between alumina and silicon nitride which is observed when an auxiliary agent is used. Since these decomposition reactions occur in the surface layer of the sintered body, the inside and the surface are different in composition, and as a result, color unevenness occurs in the sintered body. As the decomposition reaction proceeds further, the compactness of the surface layer of the sintered body becomes low,
Silicon nitride may become silicon. The sintered body having the color spots not only impairs the commercial value, but also deteriorates the mechanical properties of the surface layer portion.
【０００４】このような窒化珪素分解を抑制する方法と
しては、窒素加圧雰囲気によって分解反応を抑制しなが
ら焼結する方法、これと併用して炭素容器内に窒化珪素
及び／又は窒化硼素等の粉末を共存させる、即ち該粉末
からなるいわゆる敷き粉上に被焼成物を設置し、焼成時
の被焼成物近傍の雰囲気を制御する方法などが知られて
いる。As a method of suppressing the decomposition of silicon nitride, a method of sintering while suppressing the decomposition reaction in a nitrogen pressure atmosphere, and in combination with this method, silicon nitride and / or boron nitride, etc. in a carbon container are used. A method is known in which powders are made to coexist, that is, a material to be fired is placed on a so-called spread powder made of the powder, and the atmosphere in the vicinity of the material to be fired during firing is controlled.
【０００５】しかしながら、窒素加圧雰囲気下で焼結す
る方法では、窒素圧力を上げると分解抑制の傾向が見ら
れるが、焼成装置の制約や経済性等を考慮すると、一般
に圧力１０Ｋｇ／ｃｍ2程度の加圧が限界であり、該圧
力では分解を十分に抑制するには至らない。また、炭素
容器中に直接被焼成物を入れて焼結を行えば、被焼成体
の表面が炭化珪素化する。更に、炭素坩堝を用い、窒化
珪素又は窒化硼素等の敷き粉上に被焼成物を設置する方
法、或いはこれに１０Ｋｇ／ｃｍ2以下の窒素雰囲気加
圧を併用する方法では、表面の炭化珪素化は防止できる
が分解反応抑制効果は弱く、表面に色斑や変質層が形成
され易い等の問題点がある。However, in the method of sintering in a pressurized nitrogen atmosphere, decomposition tends to be suppressed when the nitrogen pressure is increased, but in consideration of restrictions of the firing apparatus and economical efficiency, the pressure is generally about 10 Kg / cm 2. The pressure is limited, and the pressure cannot sufficiently suppress decomposition. Further, if the object to be fired is directly put into a carbon container and is sintered, the surface of the object to be fired becomes silicon carbide. Further, in the method of using a carbon crucible and placing the object to be fired on the spread powder of silicon nitride or boron nitride, or the method of using this together with pressurization in a nitrogen atmosphere of 10 kg / cm 2 or less, the surface is converted into silicon carbide. However, there is a problem that the effect of suppressing the decomposition reaction is weak and color spots and an altered layer are easily formed on the surface.
【０００６】[0006]
【発明の解決しようとする課題】本発明の目的は、前記
問題点の解消、即ち色斑や変質層がない均質な緻密質窒
化珪素焼結体を容易に製造する方法を提供することであ
る。SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, that is, to provide a method for easily producing a homogeneous dense silicon nitride sintered body free from color spots and altered layers. .
【０００７】[0007]
【課題を解決するための手段】前記課題解決の為、本発
明者らは鋭意検討した結果、窒化珪素と酸化アルミニウ
ムの混合物を炭素質容器に入れ、窒素雰囲気中１４００
〜１９００℃の温度で一旦加熱処理を行った後混合物を
除去し、この加熱処理済みの容器中に、窒化珪素と焼結
助剤からなる被焼成成形物を入れて窒素雰囲気で焼結す
ることにより色斑や変質層がない緻密質の窒化珪素焼結
体が容易に得られることを見出し、本発明を完成するに
至った。In order to solve the above problems, as a result of intensive investigations by the present inventors, as a result, a mixture of silicon nitride and aluminum oxide was placed in a carbonaceous container and placed in a nitrogen atmosphere at 1400.
After heat-treating at a temperature of up to 1900 ° C, the mixture is removed, and a molded article to be fired consisting of silicon nitride and a sintering aid is placed in this heat-treated container and sintered in a nitrogen atmosphere. As a result, it was found that a dense silicon nitride sintered body without color spots and altered layers can be easily obtained, and the present invention has been completed.
【０００８】即ち、本発明は、炭素質容器中に窒化珪素
約５０〜９０重量％と残部酸化アルミニウムからなる混
合物を入れ、窒素雰囲気中、１４００〜１９００℃の温
度で加熱した後、該混合物を除去した容器中に、窒化珪
素と焼結助剤からなる被焼成成形物を入れ、これを窒素
雰囲気中で焼成することを特徴とする窒化珪素焼結体の
製造方法である。That is, according to the present invention, a mixture of about 50 to 90% by weight of silicon nitride and the balance of aluminum oxide is put in a carbonaceous container and heated at a temperature of 1400 to 1900 ° C. in a nitrogen atmosphere, and then the mixture is heated. A method for manufacturing a silicon nitride sintered body is characterized in that a molded product to be sintered, which is composed of silicon nitride and a sintering aid, is placed in the removed container and is sintered in a nitrogen atmosphere.
【０００９】また、本発明は、前記の加熱後の混合物を
除去した容器中に、窒化珪素約５０〜９０重量％と残部
酸化アルミニウムからなる混合物と、窒化珪素と焼結助
剤からなる被焼成成形物とを共存させ、これを窒素雰囲
気中で焼成することを特徴とする窒化珪素焼結体の製造
方法である。Further, according to the present invention, in a container from which the above-mentioned mixture after heating is removed, a mixture of about 50 to 90% by weight of silicon nitride and the balance aluminum oxide, and a material to be fired comprising silicon nitride and a sintering aid. This is a method for producing a silicon nitride sintered body, which comprises coexisting with a molded article and firing the same in a nitrogen atmosphere.
【００１０】[0010]
【発明の実施の形態】本発明で用いる炭素質容器の作製
方法としては、所望の形状の被焼成物を収納したまま加
熱装置で焼成できる非密封性の容器、望ましくは完全密
封式でない限り、蓋を有する容器であれば何れの形状で
あっても良く、このような容器としては、例えば一般に
焼成用鞘、焼成用梗鉢、焼成用坩堝などと称されている
ものでも良い。このような形態の容器でその材質が炭
素、望ましくは高緻密質の炭素からなる容器を用意す
る。その際、該容器の内壁面に、水又はエタノールやア
セトン等の揮発し易い溶剤と混練した窒化硼素の粉末を
一様に塗布して乾燥させたものとすると一層良い。BEST MODE FOR CARRYING OUT THE INVENTION As a method for producing a carbonaceous container used in the present invention, a non-sealing container that can be baked by a heating device while containing a material to be baked having a desired shape, preferably, unless it is a completely sealed type, The container may have any shape as long as it has a lid, and such a container may be, for example, those generally referred to as a firing sheath, a firing inflator, a firing crucible and the like. A container having a material of carbon, preferably a highly dense carbon, is prepared. At this time, it is more preferable that the inner wall surface of the container is uniformly coated with water or a powder of boron nitride kneaded with a solvent that easily volatilizes, such as ethanol or acetone, and dried.
【００１１】次いで、この容器内に、窒化珪素約５０〜
９０重量％と残部が酸化アルミニウムからなる混合物の
粉末、又は該粉末を金型成形などにより成形した成形物
を、容器内容積１０００ｃｍ3に対しおよそ１０〜１０
０ｇの量を入れ、常圧（約１気圧）、又は１０ｋｇ／ｃ
ｍ2程度の圧力下、窒素ガスを用いた雰囲気中で１４０
０〜１９００℃、約１００分間加熱処理を行う。この加
熱処理は１回でも良いが、望ましくは容器内の加熱処理
後の内容物を新たに未加熱の窒化珪素５０〜９０％と残
部が酸化アルミニウムからなる混合物と交換し、再度前
記と同様の条件で加熱処理する。このような加熱処理を
３〜４回程度繰り返すと良いが、容器に入れる混合物の
量が多い程、より少ない加熱処理回数でも対応できる。
加熱処理後、内容物を取り除いた容器をもって本発明で
用いる炭素質容器とする。Next, about 50 to 50 nm of silicon nitride is placed in this container.
A powder of a mixture of 90% by weight and the balance of aluminum oxide, or a molded product obtained by molding the powder by die molding or the like is used in an amount of about 10 to 10 with respect to an internal volume of 1000 cm 3.
Put 0g amount, normal pressure (about 1 atm), or 10kg / c
140 m in a nitrogen gas atmosphere under a pressure of about m 2.
Heat treatment is performed at 0 to 1900 ° C. for about 100 minutes. This heat treatment may be carried out only once, but preferably the contents after heat treatment in the container are newly replaced with a mixture of 50 to 90% of unheated silicon nitride and the balance of aluminum oxide, and the same as above. Heat treatment under the conditions. Such heat treatment may be repeated about 3 to 4 times, but the smaller the number of heat treatments, the larger the amount of the mixture to be put in the container.
After the heat treatment, the container from which the contents are removed is the carbonaceous container used in the present invention.
【００１２】このような炭素質容器に、窒化珪素粉末と
例えばＹ2Ｏ3−Ａｌ2Ｏ3系、又はＭｇＯ−Ａｌ2Ｏ3系の
ような窒化珪素の焼結に適した公知の焼結助剤を混合
し、必要に応じて高温下で分解離脱可能な成形助剤を加
えた後、混合粉末を所望の形状に成形したものを被焼成
成形物として収納する。ここで窒化珪素粉末としては特
に不純物を多く含有したものでない限り通常市販されて
いるものを用いることができ、また焼結助剤の使用量と
しては助剤種によるが、窒化珪素１００重量部に対し
て、およそ５〜１０重量部程度とする。成形方法として
は、例えば一軸加圧、冷間等方加圧（ＣＩＰ）、射出、
鋳込み等の公知の何れの方法でも良い。In such a carbonaceous container, known sintering suitable for sintering silicon nitride powder and silicon nitride such as Y 2 O 3 --Al 2 O 3 system or MgO--Al 2 O 3 system is used. After mixing the auxiliaries and, if necessary, adding a molding aid that can be decomposed and released at high temperature, the mixed powder molded into a desired shape is housed as a material to be fired. As the silicon nitride powder, a commercially available powder can be used unless it contains a large amount of impurities, and the amount of the sintering aid to be used depends on the type of the aid. On the other hand, the amount is about 5 to 10 parts by weight. As the molding method, for example, uniaxial pressing, cold isotropic pressing (CIP), injection,
Any known method such as casting may be used.
【００１３】窒化珪素と焼結助剤からなる被焼成成形物
は、前記炭素質容器中に収納したまま、常圧（約１気
圧）、望ましくは１０ｋｇ／ｃｍ2程度の圧力とした窒
素ガスを用いた雰囲気中、例えば１７００〜１９００℃
の温度でおよそ１００分間以上焼成することによって均
質かつ緻密で色斑のない窒化珪素焼結体を製造すること
ができる。The article to be fired, which is composed of silicon nitride and a sintering aid, is stored in the carbonaceous container and is kept at a normal pressure (about 1 atm), preferably about 10 kg / cm 2 of nitrogen gas. In the atmosphere used, for example, 1700 to 1900 ° C
By firing at a temperature of about 100 minutes or more, it is possible to manufacture a homogeneous and dense silicon nitride sintered body without color spots.
【００１４】また、好ましくは、窒化珪素と焼結助剤か
らなる被焼成成形物を前記加熱処理をした炭素質容器中
に入れる際、新たに窒化珪素約５０〜９０重量％と残部
酸化アルミニウムからなる混合粉末又はその成形物と、
被焼成成形物とを共に１つの容器内に入れ、常圧（約１
気圧）、望ましくは１０ｋｇ／ｃｍ2程度の圧力下、窒
素ガスを用いた窒素雰囲気中、例えば１７００〜１９０
０℃の温度でおよそ１００分間以上焼成することによっ
てより均質かつ緻密で色斑のない窒化珪素焼結体を製造
することができる。ここで窒化珪素と酸化アルミニウム
との混合物は、被焼成成形物と概ね等重量となる量を容
器に入れると良い。また、窒化珪素と酸化アルミニウム
との混合物と、窒化珪素と焼結助剤からなる被焼成成形
物は、接触しないように容器中に共存させるのが望まし
い。Further, preferably, when a molded article to be fired consisting of silicon nitride and a sintering aid is put into the heat-treated carbonaceous container, about 50 to 90% by weight of silicon nitride and the balance aluminum oxide are newly added. Mixed powder or molded product thereof,
Put the product to be fired together in one container and press at atmospheric pressure (about 1
Atmospheric pressure), preferably under a pressure of about 10 kg / cm 2 in a nitrogen atmosphere using nitrogen gas, for example, 1700 to 190
By firing at a temperature of 0 ° C. for about 100 minutes or more, it is possible to manufacture a more homogeneous, dense, and color-spotless silicon nitride sintered body. Here, the mixture of silicon nitride and aluminum oxide is preferably placed in a container in an amount that is approximately equal to the weight of the material to be fired. Further, it is desirable that the mixture of silicon nitride and aluminum oxide and the product to be fired consisting of silicon nitride and a sintering aid be made to coexist in a container so as not to come into contact with each other.
【００１５】[0015]
【作用と効果】窒化珪素と酸化アルミニウムの混合物を
炭素質容器に入れ、窒素雰囲気中、１４００〜１９００
℃の温度で加熱すると、この窒化珪素と酸化アルミニウ
ムが反応して、一酸化珪素と窒素を放出し、一酸化珪素
の一部が炭素質容器の内壁に捕捉される。このため、こ
のような加熱処理済みの炭素容器を用いて、窒化珪素と
焼結助剤からなる被焼成成形物を焼結すれば、焼結過程
中で、容器内に一酸化珪素を含む雰囲気が形成される
為、被焼成成形物の分解反応が抑制され、均質で色斑の
ない窒化珪素焼結体を製造することが可能となる。尚、
窒化珪素と酸化アルミニウムの混合物の配合割合を、窒
化珪素５０〜９０重量％で残部酸化アルミニウムとする
のは、窒化珪素が９０％を越えると、放出される一酸化
珪素の量が分解反応を抑制するに必要とされる量に比べ
ると不足し、窒化珪素が５０％未満の場合は、混合物が
容器に溶着することがあるからである。また、加熱処理
温度が、１４００℃未満では窒化珪素と酸化アルミニウ
ムが反応せず、一酸化珪素が発生しない為、また１９０
０℃を越えると容器内に珪素酸化物が生成し易い為、該
混合物の加熱処理は１４００〜１９００℃の温度で行
う。[Operation and effect] A mixture of silicon nitride and aluminum oxide is placed in a carbonaceous container and placed in a nitrogen atmosphere at 1400 to 1900.
When heated at a temperature of ° C, the silicon nitride and aluminum oxide react with each other to release silicon monoxide and nitrogen, and a part of the silicon monoxide is captured on the inner wall of the carbonaceous container. For this reason, if a molded article to be fired consisting of silicon nitride and a sintering aid is sintered using such a heat-treated carbon container, an atmosphere containing silicon monoxide will be contained in the container during the sintering process. As a result, the decomposition reaction of the material to be fired is suppressed, and it is possible to manufacture a homogeneous silicon nitride sintered body without color spots. still,
The mixing ratio of the mixture of silicon nitride and aluminum oxide is 50 to 90% by weight of silicon nitride and the balance is aluminum oxide. When silicon nitride exceeds 90%, the amount of silicon monoxide released suppresses the decomposition reaction. This is because the amount is insufficient as compared with the amount required to do so, and when the silicon nitride is less than 50%, the mixture may be welded to the container. If the heat treatment temperature is lower than 1400 ° C., silicon nitride and aluminum oxide do not react with each other and silicon monoxide is not generated.
If the temperature exceeds 0 ° C, silicon oxide is likely to be generated in the container, so the heat treatment of the mixture is performed at a temperature of 1400 to 1900 ° C.
【００１６】又、前記加熱処理後の炭素質容器内に、新
たに窒化珪素５０〜９０重量％で残部酸化アルミニウム
からなる混合物を存在させたまま、窒化珪素と焼結助剤
からなる被焼成成形物を収納して焼結すれば、容器内に
共存する該混合物から発生する多量の一酸化珪素ガスに
より被焼成成形物に対する分解抑制作用はより強力なも
のとなる。更に、焼結体の製造の都度、炭素質容器に新
たな窒化珪素と酸化アルミニウムの混合物を共存させて
焼結すれば、分解抑制作用を高めることができ、均一な
性状で表面及び内部とも全く色斑の無い緻密質窒化珪素
焼結体を常時安定に得ることが可能である。Further, in the carbonaceous container after the heat treatment, while a new mixture of 50 to 90% by weight of silicon nitride and the balance of aluminum oxide is still present, firing-compacting molding comprising silicon nitride and a sintering aid. When the substance is stored and sintered, the large amount of silicon monoxide gas generated from the mixture coexisting in the container makes the effect of suppressing decomposition of the molded product to be fired stronger. Furthermore, if a new mixture of silicon nitride and aluminum oxide is co-sintered in a carbonaceous container each time the sintered body is manufactured, the decomposition suppressing action can be enhanced, and the surface and the inside can be completely formed with uniform properties. It is possible to always stably obtain a dense silicon nitride sintered body without color spots.
【００１７】更に、本発明の方法により作製した加熱処
理済みの炭素質容器は、その使用により分解抑制効果が
劣化した場合、再度窒化珪素と酸化アルミニウムの混合
物を入れて前記加熱処理を行うことによって分解抑制効
果を再付与さすことができ、適宜該加熱処理を履行すれ
ば何度も繰り返し窒化珪素を焼結する為の焼成用容器と
して使用することができる。Further, in the case of the heat-treated carbonaceous container produced by the method of the present invention, when the decomposition suppressing effect is deteriorated by its use, the heat treatment is conducted again by adding a mixture of silicon nitride and aluminum oxide. The decomposition suppressing effect can be imparted again, and if the heat treatment is appropriately carried out, it can be used as a firing container for repeatedly sintering silicon nitride.
【００１８】[0018]
【実施例】以下、実施例により本発明を具体的に説明す
る。 ［実施例１］ 内径２００ｍｍ、高さ４０ｍｍで蓋を有
する炭素質坩堝の内壁に、窒化硼素粉末をエタノールで
混練したものを一様に塗布し乾燥させた。次いで表１に
記した配合割合になるよう調整した窒化珪素と酸化アル
ミニウムの混合粉末を各配合割合別に金型成形し、それ
ぞれ直径約２０ｍｍ、高さ約４．５〜５ｍｍ、重量約４
ｇの円柱状成形物を各配合割合毎に６個ずつ作製した。
炭素質坩堝内に同一の配合割合の成形物６個を入れて蓋
を付け、市販の加熱装置で圧力約１０ｋｇ／ｃｍ2の窒
素雰囲気下、１８００℃、１００分の加熱処理を行っ
た。このような加熱処理をそれぞれ配合割合を変えた成
形物毎に坩堝を変えて行い、４種の加熱処理済み坩堝を
作製した。加熱処理後、内容物を除去した各坩堝を容器
とし、該容器毎に、比表面積６．８ｍ2／ｇの窒化珪素
粉末９０重量％と焼結助剤として６重量％のＹ2Ｏ3及び
４重量％のＡｌ2Ｏ3からなる混合粉末を圧力１ｔ／ｃｍ
2でＣＩＰ成形した約４ｇの円柱成形物５個を被焼成成
形物としてそれぞれ収納した。これを、圧力約１０ｋｇ
／ｃｍ2の窒素雰囲気下で１８００℃、１００分焼成す
ることによって、窒化珪素焼結体（本発明品１〜３）を
作製した。得られた各焼結体は、相対密度（％）及び焼
成前後の重量変化として焼成前の被焼成成形物から焼結
体への重量減少率（％）、表面の色斑、及び表面と該焼
結体を切断した内部の色斑を調べた。その結果を表１に
合わせて記す。The present invention will be described below in detail with reference to examples. [Example 1] A carbonaceous crucible having an inner diameter of 200 mm and a height of 40 mm and having a lid was uniformly coated with a mixture of boron nitride powder and ethanol, and dried. Then, a mixed powder of silicon nitride and aluminum oxide adjusted to have the blending ratio shown in Table 1 is molded into molds having respective blending ratios, each having a diameter of about 20 mm, a height of about 4.5 to 5 mm, and a weight of about 4 mm.
Six cylindrical molded products of g were prepared for each mixing ratio.
Six moldings having the same compounding ratio were placed in a carbonaceous crucible, a lid was attached, and heat treatment was performed at 1800 ° C. for 100 minutes in a nitrogen atmosphere with a pressure of about 10 kg / cm 2 by a commercially available heating device. Such heat treatment was performed by changing the crucible for each molded product having a different blending ratio to prepare four types of heat-treated crucibles. After the heat treatment, each crucible from which the contents were removed was used as a container, and for each container, 90% by weight of silicon nitride powder having a specific surface area of 6.8 m 2 / g and 6% by weight of Y 2 O 3 as a sintering aid and A mixed powder of 4 wt% Al 2 O 3 was applied at a pressure of 1 t / cm
Five cylindrical molded products of about 4 g which were CIP molded in 2 were housed as molded products to be fired. This is pressure about 10kg
A silicon nitride sintered body (Products 1 to 3 of the present invention) was produced by firing at 1800 ° C. for 100 minutes in a nitrogen atmosphere of / cm 2 . Each of the obtained sintered bodies had a relative density (%) and a weight reduction rate (%) from the article to be fired before firing to a sintered body as a change in weight before and after firing, surface color unevenness, and The color spots inside the sintered body were examined. The results are also shown in Table 1.
【００１９】[0019]
【表１】 [Table 1]
【００２０】［実施例２］ 内径２００ｍｍ、高さ４０
ｍｍで蓋を有する炭素質坩堝の内壁に、窒化硼素粉末を
エタノールで混練したものを一様に塗布し乾燥させた。
次いで窒化珪素７０重量％と酸化アルミニウム３０重量
％からなる混合粉末を金型成形し、直径約２０ｍｍ、高
さ約５ｍｍ、重量約４ｇの円柱状形状成形物を作製し
た。坩堝内にこのような成形物６個を入れて蓋を付け、
市販の加熱装置で圧力約１０ｋｇ／ｃｍ2の窒素雰囲気
下、表２に記した焼成温度で、１００分の加熱処理をそ
れぞれ行った。加熱処理後、坩堝内の内容物を除去した
各坩堝を容器とし、該容器に、比表面積６．８ｍ2／ｇ
の窒化珪素粉末９０重量％と焼結助剤として６重量％の
Ｙ2Ｏ3及び４重量％のＡｌ2Ｏ3からなる混合粉末を圧力
１ｔ／ｃｍ2でＣＩＰ成形した重量４ｇの円柱成形物５
個を被焼成成形物としてそれぞれ収納した。これを、圧
力約１０ｋｇ／ｃｍ2の窒素雰囲気下で１８００℃、１
００分焼成することによって、窒化珪素焼結体（本発明
品４〜５）を作製した。得られた各焼結体は、相対密度
（％）及び焼成前の被焼成成形物から焼結体への重量減
少率（％）、表面の色斑、及び表面と切断した内部の色
斑を調べた。その結果を表２に合わせて記す。[Embodiment 2] Inner diameter 200 mm, height 40
A carbonaceous crucible having a lid with a diameter of mm was uniformly coated with a mixture of boron nitride powder and ethanol and dried.
Next, a mixed powder consisting of 70% by weight of silicon nitride and 30% by weight of aluminum oxide was die-molded to produce a cylindrical shaped article having a diameter of about 20 mm, a height of about 5 mm and a weight of about 4 g. Put 6 such moldings in the crucible and attach the lid,
The heat treatment was performed for 100 minutes at a firing temperature shown in Table 2 under a nitrogen atmosphere with a pressure of about 10 kg / cm 2 using a commercially available heating device. After the heat treatment, each crucible from which the contents in the crucible were removed was used as a container, and the specific surface area of the container was 6.8 m 2 / g.
CIP molding of a mixed powder consisting of 90% by weight of the silicon nitride powder of No. 3 , 6% by weight of Y 2 O 3 and 4% by weight of Al 2 O 3 as a sintering aid, and CIP-molded at a pressure of 1 t / cm 2 . 5
Each piece was stored as a molded article to be fired. This is 1800 ° C. under a nitrogen atmosphere at a pressure of about 10 kg / cm 2 ,
By firing for 00 minutes, silicon nitride sintered bodies (invention products 4 to 5) were produced. Each of the obtained sintered bodies had a relative density (%), a weight reduction rate (%) from the material to be fired before firing to the sintered body, a surface color spot, and an internal color spot cut from the surface. Examined. The results are also shown in Table 2.
【００２１】[0021]
【表２】 [Table 2]
【００２２】［実施例３］ 内径２００ｍｍ、高さ４０
ｍｍで蓋を有する炭素質坩堝の内壁に、窒化硼素粉末を
エタノールで混練したものを一様に塗布し乾燥させた。
次いで窒化珪素７０重量％と酸化アルミニウム３０重量
％からなる混合粉末を金型成形し、直径約２０ｍｍ、高
さ約５ｍｍ、重量約４ｇの円柱状形状成形物を作製し
た。坩堝内に該成形物６個を入れて蓋を付け、市販の加
熱装置で圧力約１０ｋｇ／ｃｍ2の窒素雰囲気下、１８
００℃、１００分の加熱処理を行った。加熱処理後、坩
堝内の内容物を除去し、この坩堝に更に、前記同様に作
製した窒化珪素と酸化アルミニウムとの混合物よりなる
成形物６個を入れ前期同様の加熱処理を行った。この一
連の加熱処理を計５回繰り返し行った後、内容物を除去
した坩堝を容器とし、該容器に、比表面積６．８ｍ2／
ｇの窒化珪素粉末９０重量％と焼結助剤として６重量％
のＹ2Ｏ3及び４重量％のＡｌ2Ｏ3からなる混合粉末を圧
力１ｔ／ｃｍ2でＣＩＰ成形した重量４ｇの円柱成形物
５個を被焼成成形物として収納した。これを、圧力約１
０ｋｇ／ｃｍ2の窒素雰囲気下で１８００℃、１００分
焼成することによって、窒化珪素焼結体を作製した。得
られた焼結体は、焼成前の被焼成成形物から焼結体への
重量減少率が０．８％であり、相対密度９７％で色斑が
表面及び内部とも無い均質な窒化珪素焼結体であった。[Embodiment 3] Inner diameter 200 mm, height 40
A carbonaceous crucible having a lid with a diameter of mm was uniformly coated with a mixture of boron nitride powder and ethanol and dried.
Next, a mixed powder consisting of 70% by weight of silicon nitride and 30% by weight of aluminum oxide was die-molded to produce a cylindrical shaped article having a diameter of about 20 mm, a height of about 5 mm and a weight of about 4 g. Put the six molded products in a crucible and attach a lid, and use a commercially available heating device under a nitrogen atmosphere at a pressure of about 10 kg / cm 2 for 18 hours.
Heat treatment was performed at 00 ° C. for 100 minutes. After the heat treatment, the contents in the crucible were removed, and six molded products made of the mixture of silicon nitride and aluminum oxide prepared in the same manner as above were further put in this crucible and the same heat treatment as the previous period was performed. After repeating this series of heat treatments a total of 5 times, the crucible from which the contents were removed was used as a container, and the container had a specific surface area of 6.8 m 2 /
90% by weight of silicon nitride powder of 6 g and 6% by weight as a sintering aid
The mixed powder consisting of Y 2 O 3 and 4% by weight of Al 2 O 3 was CIP-molded at a pressure of 1 t / cm 2 , and five cylindrical molded products having a weight of 4 g were stored as molded products to be fired. This is pressure about 1
A silicon nitride sintered body was produced by firing at 1800 ° C. for 100 minutes in a nitrogen atmosphere of 0 kg / cm 2 . The obtained sintered body had a weight loss rate of 0.8% from the material to be fired before firing, a relative density of 97%, and a homogeneous silicon nitride firing with no color unevenness on the surface and inside. It was a union.
【００２３】［実施例４］ 実施例３と同様の方法で加
熱処理することにより作製した容器に、比表面積７．４
ｍ2／ｇの窒化珪素粉末８９重量％と焼結助剤として６
重量％のＹ2Ｏ3と５重量％のＡｌ2Ｏ3からなる混合粉末
を圧力１ｔ／ｃｍ2でＣＩＰ成形した重量４ｇの円柱成
形物５個を被焼成成形物として収納した。これを、圧力
約１０ｋｇ／ｃｍ2の窒素雰囲気下で１８００℃、１０
０分焼成することによって、窒化珪素焼結体を作製し
た。得られた焼結体は、焼成前の被焼成成形物から焼結
体への重量減少率が１．４％であり、相対密度９７％で
色斑が表面及び内部とも無い均質な窒化珪素焼結体であ
った。Example 4 A container prepared by heat treatment in the same manner as in Example 3 had a specific surface area of 7.4.
89% by weight of m 2 / g silicon nitride powder and 6 as a sintering aid
Five columnar molded products of 4 g in weight, which were CIP-molded with a powder mixture of Y 2 O 3 by weight% and Al 2 O 3 by 5% by weight at a pressure of 1 t / cm 2 , were stored as molded products to be fired. This was heated at 1800 ° C. for 10 times in a nitrogen atmosphere at a pressure of about 10 kg / cm 2.
A silicon nitride sintered body was produced by firing for 0 minutes. The obtained sintered body had a weight loss rate of 1.4% from the material to be fired before firing, a relative density of 97%, and a homogeneous silicon nitride fired with no color spots on the surface and inside. It was a union.
【００２４】［実施例５］ 実施例３と同様の方法で加
熱処理することにより作製した容器に、比表面積６．８
ｍ2／ｇの窒化珪素粉末９０重量％と焼結助剤として６
重量％のＹ2Ｏ3及び４重量％のＡｌ2Ｏ3からなる混合粉
末を圧力１ｔ／ｃｍ2でＣＩＰ成形した４ｇの円柱成形
物５個を被焼成成形物として収納し、更に同容器内に被
焼成成形物と接触しないように、窒化珪素９０重量％と
酸化アルミニウム１０重量％からなる混合粉末を金型成
形した約４ｇの成形物５個を共存させ、これを、圧力約
１０ｋｇ／ｃｍ2の窒素雰囲気下で１８００℃、１００
分焼成することによって、窒化珪素焼結体を作製した。
得られた焼結体は、焼成前の被焼成成形物から焼結体へ
の重量減少率が０．３％であり、相対密度９７％で色斑
が表面及び内部とも無い均質な窒化珪素焼結体であっ
た。[Embodiment 5] A container prepared by heat treatment in the same manner as in Embodiment 3 has a specific surface area of 6.8.
90% by weight of m 2 / g silicon nitride powder and 6 as a sintering aid
5 g of a columnar molded product of 4 g obtained by CIP-molding a mixed powder of Y 2 O 3 by weight% and Al 2 O 3 by 4% by weight at a pressure of 1 t / cm 2 was housed as a product to be fired, and further in the same container. In order to avoid contact with the product to be fired, approximately 4 g of 5 molded products obtained by mold-molding a mixed powder of 90% by weight of silicon nitride and 10% by weight of aluminum oxide were allowed to coexist. 1800 ° C, 100 in 2 nitrogen atmosphere
A silicon nitride sintered body was produced by firing for minutes.
The obtained sintered body had a weight loss rate of 0.3% from the material to be fired before firing to a sintered body, a relative density of 97%, and a homogeneous silicon nitride firing with no color unevenness on the surface and inside. It was a union.
【００２５】次に参考のため本発明から外れる比較例を
記す。 ［比較例１］ 内径２００ｍｍ、高さ４０ｍｍで蓋を有
する炭素質坩堝の内壁に、窒化硼素粉末をエタノールで
混練したものを一様に塗布し乾燥させたものを容器と
し、該容器内に比表面積６．８ｍ2／ｇの窒化珪素粉末
９０重量％と焼結助剤として６重量％のＹ2Ｏ3及び４重
量％のＡｌ2Ｏ3からなる混合粉末を圧力１ｔ／ｃｍ2で
ＣＩＰ成形した４ｇの円柱成形物５個を被焼成成形物と
して収納した。これを、圧力約１０ｋｇ／ｃｍ2の窒素
雰囲気下で１８００℃、１００分焼成することによっ
て、窒化珪素焼結体を作製した。得られた焼結体は、焼
成前の被焼成成形物から焼結体への重量減少率が５．０
％と大きく、焼成中に窒化珪素の一部が分解反応を起こ
したことが窺われ、また焼結体表面と該焼結体内部の色
は異なっており、鮮明な色斑が表面及び内部とも見られ
た窒化珪素焼結体であった。Next, comparative examples which deviate from the present invention will be described for reference. [Comparative Example 1] A carbonaceous crucible having an inner diameter of 200 mm and a height of 40 mm and a lid having a lid was uniformly coated with a mixture of boron nitride powder and ethanol, and dried to form a container. CIP molding of a mixed powder consisting of 90% by weight of silicon nitride powder having a surface area of 6.8 m 2 / g and 6% by weight of Y 2 O 3 and 4% by weight of Al 2 O 3 as a sintering aid at a pressure of 1 t / cm 2. 5 g of the 4 g cylindrical molded product was stored as a molded product. This was fired in a nitrogen atmosphere at a pressure of about 10 kg / cm 2 at 1800 ° C. for 100 minutes to produce a silicon nitride sintered body. The obtained sintered body has a weight reduction rate of 5.0 from the material to be fired before firing to the sintered body.
%, Which indicates that a part of silicon nitride undergoes a decomposition reaction during firing, and the color of the surface of the sintered body is different from that of the inside of the sintered body. It was the observed silicon nitride sintered body.
【００２６】［比較例２］ 内径２００ｍｍ、高さ４０
ｍｍで蓋を有する炭素質坩堝の内壁に、窒化硼素粉末を
エタノールで混練したものを一様に塗布し乾燥させた。
次いで窒化珪素９５重量％と酸化アルミニウム５重量％
からなる混合粉末を金型成形し、直径約２０ｍｍ、高さ
約５ｍｍ、重量約４ｇの円柱状形状成形物を作製した。
坩堝内にこのような成形物６個を入れて蓋を付け、市販
の加熱装置で圧力約１０ｋｇ／ｃｍ2の窒素雰囲気下、
１８００℃で、１００分の加熱処理を行った。加熱処理
後、坩堝内の内容物を除去した坩堝を容器とし、該容器
に、比表面積６．８ｍ2／ｇの窒化珪素粉末９０重量％
と焼結助剤として６重量％のＹ2Ｏ3及び４重量％のＡｌ
2Ｏ3からなる混合粉末を圧力１ｔ／ｃｍ2でＣＩＰ成形
した約４ｇの円柱成形物５個を被焼成成形物としてそれ
ぞれ収納した。これを、圧力約１０ｋｇ／ｃｍ2の窒素
雰囲気下で１８００℃、１００分焼成した。得られた窒
化珪素焼結体は、焼成前の被焼成成形物から焼結体への
重量減少率が３．５％と比較的大きく、焼成中に窒化珪
素の一部が分解反応を起こしたことが窺われ、表面及び
内部とも色斑が見られた。[Comparative Example 2] Inner diameter 200 mm, height 40
A carbonaceous crucible having a lid with a diameter of mm was uniformly coated with a mixture of boron nitride powder and ethanol and dried.
Then 95% by weight of silicon nitride and 5% by weight of aluminum oxide
The mixed powder consisting of was molded into a mold to produce a cylindrical molded product having a diameter of about 20 mm, a height of about 5 mm and a weight of about 4 g.
Put 6 such moldings in a crucible and attach a lid, and use a commercially available heating device under a nitrogen atmosphere with a pressure of about 10 kg / cm 2 .
Heat treatment was performed at 1800 ° C. for 100 minutes. After the heat treatment, the crucible from which the contents in the crucible were removed was used as a container, and the container had 90% by weight of silicon nitride powder having a specific surface area of 6.8 m 2 / g.
And 6% by weight Y 2 O 3 and 4% by weight Al as sintering aids
Five cylindrical molded products of about 4 g, which were CIP-molded with a mixed powder of 2 O 3 at a pressure of 1 t / cm 2 , were housed as molded products. This was fired at 1800 ° C. for 100 minutes in a nitrogen atmosphere with a pressure of about 10 kg / cm 2 . The obtained silicon nitride sintered body had a relatively large weight reduction rate from the material to be fired before firing to a sintered body of 3.5%, and a part of the silicon nitride decomposed during firing. As a result, color spots were observed both on the surface and inside.
Claims (2)
量％と残部酸化アルミニウムからなる混合物を入れ、窒
素雰囲気中、１４００〜１９００℃の温度で加熱した
後、該混合物を除去した容器中に、窒化珪素と焼結助剤
からなる被焼成成形物を入れ、これを窒素雰囲気中で焼
成することを特徴とする窒化珪素焼結体の製造方法。1. A container obtained by placing a mixture of about 50 to 90% by weight of silicon nitride and the balance aluminum oxide in a carbonaceous container, heating the mixture at a temperature of 1400 to 1900 ° C. in a nitrogen atmosphere, and then removing the mixture. A method for producing a silicon nitride sintered body, comprising: placing a molded article to be fired, which comprises silicon nitride and a sintering aid, and firing the molded article in a nitrogen atmosphere.
た容器中に、窒化珪素約５０〜９０重量％と残部酸化ア
ルミニウムからなる混合物と、窒化珪素と焼結助剤から
なる被焼成成形物とを共存させ、これを窒素雰囲気中で
焼成することを特徴とする窒化珪素焼結体の製造方法。2. A container from which the mixture after heating according to claim 1 has been removed, and a mixture of about 50 to 90% by weight of silicon nitride and the balance of aluminum oxide, and a material to be sintered formed of silicon nitride and a sintering aid. A method for producing a silicon nitride sintered body, which comprises coexisting with a material and firing the same in a nitrogen atmosphere.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8069222A JPH09235165A (en) | 1996-02-29 | 1996-02-29 | Production of sintered compact of silicon nitride |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8069222A JPH09235165A (en) | 1996-02-29 | 1996-02-29 | Production of sintered compact of silicon nitride |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09235165A true JPH09235165A (en) | 1997-09-09 |
Family
ID=13396492
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8069222A Withdrawn JPH09235165A (en) | 1996-02-29 | 1996-02-29 | Production of sintered compact of silicon nitride |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09235165A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013146789A1 (en) * | 2012-03-26 | 2013-10-03 | 日立金属株式会社 | Sintered silicon nitride substrate and process for producing same |
| WO2021241583A1 (en) | 2020-05-26 | 2021-12-02 | 株式会社 東芝 | Silicon nitride sintered body, wear-resistant member using same, and method for producing silicon nitride sintered body |
-
1996
- 1996-02-29 JP JP8069222A patent/JPH09235165A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013146789A1 (en) * | 2012-03-26 | 2013-10-03 | 日立金属株式会社 | Sintered silicon nitride substrate and process for producing same |
| WO2021241583A1 (en) | 2020-05-26 | 2021-12-02 | 株式会社 東芝 | Silicon nitride sintered body, wear-resistant member using same, and method for producing silicon nitride sintered body |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPS623113B2 (en) | ||
| JPH0260633B2 (en) | ||
| US4564601A (en) | Shaped polycrystalline silicon carbide articles and isostatic hot-pressing process | |
| JPH0577632B2 (en) | ||
| JPH07172932A (en) | Preparation of silicon nitride base material, material prepared by this method and its use | |
| JP3667121B2 (en) | Boron carbide sintered body and manufacturing method thereof | |
| JPH09235165A (en) | Production of sintered compact of silicon nitride | |
| JPS63260868A (en) | Aluminum nitride sintered body and manufacture | |
| JP4578009B2 (en) | Method for producing nitrogen-containing inorganic compound | |
| SU1074402A3 (en) | Method of producing silicon nitride-base articles | |
| JPH046159A (en) | Production of silicon nitride-based ceramics sintered body | |
| US6013321A (en) | Method to manufacture phosphate bonded ceramics | |
| JPH0920565A (en) | Degreasing of formed inorganic powder | |
| JPS6389462A (en) | Manufacture of silicon nitride base sintered body | |
| JPH0733528A (en) | Composite sintered ceramic, its production and semiconductor production jig made therefrom | |
| JP2002526374A (en) | Manufacturing method of composite material and representative material of this composite material | |
| JPH0146472B2 (en) | ||
| JP3839514B2 (en) | Silicon nitride sintered body and method for producing the same | |
| JPS5939769A (en) | Method of sintering silicon nitride | |
| JP2747627B2 (en) | Silicon nitride based sintered body and method for producing the same | |
| JPH05148035A (en) | Production of sintered silicon nitride | |
| JPS63277572A (en) | Production of sintered aluminum nitride | |
| CN118084540A (en) | Ceramic slurry, coating for improving corrosion resistance of carbon-carbon composite material and preparation method of coating | |
| JP2947718B2 (en) | Method for producing silicon nitride based sintered body | |
| JPH07113102A (en) | Production of sintered compact |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A761 | Written withdrawal of application |
Free format text: JAPANESE INTERMEDIATE CODE: A761 Effective date: 20041202 |