JPH05208870A - Silicon nitride sintered product - Google Patents
Silicon nitride sintered productInfo
- Publication number
- JPH05208870A JPH05208870A JP4014988A JP1498892A JPH05208870A JP H05208870 A JPH05208870 A JP H05208870A JP 4014988 A JP4014988 A JP 4014988A JP 1498892 A JP1498892 A JP 1498892A JP H05208870 A JPH05208870 A JP H05208870A
- Authority
- JP
- Japan
- Prior art keywords
- silicon nitride
- sintered body
- weight
- sintered product
- sintering
- 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.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、耐酸化特性に優れた窒
化ケイ素系焼結体に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicon nitride-based sintered body excellent in oxidation resistance.
【０００２】[0002]
【従来の技術】セラミックス系の構造用材料としては、
従来から、主として窒化ケイ素系焼結体、炭化ケイ素系
焼結体、 Si-Al-O-Nを主構成元素とするサイアロン系焼
結体等が使用されてきた。中でも、窒化ケイ素系焼結体
は、炭化ケイ素系焼結体やサイアロン系焼結体に比べて
高強度を有し、さらに破壊靭性値に優れる等の特徴を有
しており、自動車部品用部材、ガスタ―ビン翼等を始め
として、各種の高強度耐熱構造用材料に応用が試みられ
ている。2. Description of the Related Art As a ceramic-based structural material,
Conventionally, a silicon nitride-based sintered body, a silicon carbide-based sintered body, a sialon-based sintered body containing Si-Al-ON as a main constituent element, and the like have been mainly used. Among them, the silicon nitride-based sintered body has characteristics such as higher strength than the silicon carbide-based sintered body and the sialon-based sintered body, and further has an excellent fracture toughness value. It has been tried to be applied to various high-strength heat-resistant structural materials, including gas turbine blades.
【０００３】ところで、窒化ケイ素自身は焼結性が極め
て悪いため、従来より各種の焼結方法が試みられてお
り、現状では主として添加物による液相焼結が用いられ
ている。上記した窒化ケイ素の焼結助剤として働く添加
物としては、希土類元素の酸化物、酸化マグネシウム、
酸化アルミニウム、窒化アルミニウム等や、ハフニウ
ム、タンタル、ニオブ等の酸化物、炭化物、ケイ化物等
が挙げられ、単独またはこれらの組合せにより使用され
ている。このような焼結助剤の組み合わせとしては、例
えば酸化イットリウム―酸化アルミニウム−窒化アルミ
ニウム−Hf、Ta、Nb等の酸化物系（特公平 1-16791号公
報参照）、希土類酸化物―Hf、Ta、Nb等の酸化物系また
は希土類酸化物―Hf、Ta、Nb等の酸化物−窒化アルミニ
ウム系（特開昭 60-290718号公報参照）等が知られてい
る。By the way, since silicon nitride itself has extremely poor sinterability, various sintering methods have been tried so far, and at present, liquid phase sintering using additives is mainly used. As the additive that acts as a sintering aid for the above-mentioned silicon nitride, oxides of rare earth elements, magnesium oxide,
Examples thereof include aluminum oxide, aluminum nitride and the like, oxides such as hafnium, tantalum and niobium, carbides and silicides, which are used alone or in combination. Examples of combinations of such sintering aids include yttrium oxide-aluminum oxide-aluminum nitride-oxide systems such as Hf, Ta, and Nb (see Japanese Patent Publication No. 1-16791), rare earth oxides-Hf, Ta. , Oxides such as Nb and rare earth oxides-oxides such as Hf, Ta and Nb-aluminum nitride (see JP-A-60-290718) and the like are known.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上記し
たような焼結助剤を用いた窒化ケイ素系焼結体は、焼成
時に一旦液相を形成し、この液相を利用して緻密質な焼
結体として得ているため、液相形成成分が焼結後に粒界
に残存し、この粒界構成相に起因して、耐酸化性に劣る
という問題を有していた。すなわち焼結助剤としては、
酸化イットリウムが主として使用されているが、酸化イ
ットリウムを使用した窒化ケイ素焼結体は、イットリウ
ムを含む粒界相に起因して、特に高温で酸化されやすい
ために、高温雰囲気中での強度劣化が大きいという問題
を有していた。However, the silicon nitride-based sintered body using the above-mentioned sintering aid once forms a liquid phase at the time of firing and utilizes this liquid phase to perform a dense firing. Since it was obtained as a bound product, the liquid phase forming component remained at the grain boundaries after sintering, and there was a problem that the oxidation resistance was poor due to this grain boundary constituent phase. That is, as a sintering aid,
Yttrium oxide is mainly used, but the silicon nitride sintered body using yttrium oxide is likely to be oxidized particularly at high temperature due to the grain boundary phase containing yttrium, so that strength deterioration in a high temperature atmosphere is caused. Had the problem of being big.
【０００５】上述したように、窒化ケイ素の焼結助剤と
して使用される酸化イットリウムは、緻密質で機械的強
度に優れた窒化ケイ素系焼結体を得ることを可能にする
半面、焼結後に粒界に残存するイットリウムを含む化合
物に起因して、耐酸化性を劣化させてしまうという問題
を有していた。このようなことから、焼結体密度、機械
的強度等をあまり低下させることなく、耐酸化特性に優
れた窒化ケイ素系焼結体を得ることが強く望まれてい
る。As described above, yttrium oxide used as a sintering aid for silicon nitride makes it possible to obtain a silicon nitride-based sintered body which is dense and has excellent mechanical strength. There is a problem that the oxidation resistance is deteriorated due to the compound containing yttrium remaining at the grain boundaries. From this, it is strongly desired to obtain a silicon nitride-based sintered body having excellent oxidation resistance characteristics without significantly lowering the sintered body density, mechanical strength, or the like.
【０００６】本発明は、このような課題に対処するため
になされたもので、焼結体密度や機械的強度に優れると
共に、耐酸化特性に優れた窒化ケイ素系焼結体を提供す
ることを目的としている。The present invention has been made to solve the above problems, and it is an object of the present invention to provide a silicon nitride-based sintered body which is excellent in the density and mechanical strength of the sintered body and is excellent in oxidation resistance. Has a purpose.
【０００７】[0007]
【課題を解決するための手段と作用】本発明の窒化ケイ
素系焼結体は、焼結助剤として、少なくとも酸化イッテ
ルビウムを 1重量％〜10重量％および窒化アルミニウム
を 1重量％〜10重量％含み、残部が実質的に窒化ケイ素
からなる混合物を成形、焼成してなることを特徴として
いる。また、本発明の窒化ケイ素系焼結体は、焼結体母
相がβ- Si3 N 4 および／またはα′- Si3 N 4 からな
り、前記焼結体母相の結晶粒界にYbを含む結晶性化合物
が少なくとも存在することを特徴としている。Means and Actions for Solving the Problems The silicon nitride-based sintered body of the present invention comprises, as a sintering aid, at least 1% by weight to 10% by weight of ytterbium oxide and 1% to 10% by weight of aluminum nitride. It is characterized in that a mixture containing it and the rest being substantially composed of silicon nitride is molded and fired. Further, in the silicon nitride-based sintered body of the present invention, the sintered body mother phase is composed of β-Si 3 N 4 and / or α′-Si 3 N 4 , and Yb is contained in the crystal grain boundary of the sintered body mother phase. It is characterized in that at least a crystalline compound containing is present.
【０００８】本発明の窒化ケイ素系焼結体の主原料とな
る窒化ケイ素としては、平均粒径が1μm 以下で、その
構成相の80％以上がα相であるものが好ましい。平均粒
径は微細なものほど焼結性が高くなるため好ましい。こ
のような窒化ケイ素原料による焼結体母体は、その主構
成相がβ- Si3 N 4 相からなり、例えば 10%以下程度の
比率でα′- Si3 N 4 相を含むものとなる。As silicon nitride as a main raw material of the silicon nitride-based sintered body of the present invention, one having an average particle size of 1 μm or less and 80% or more of its constituent phases being α phase is preferable. The finer the average particle size, the higher the sinterability, which is preferable. Such a sintered body matrix made of a silicon nitride raw material has a β-Si 3 N 4 phase as a main constituent phase, and contains an α′-Si 3 N 4 phase at a ratio of, for example, about 10% or less.
【０００９】また、本発明で焼結助剤として使用する酸
化イッテルビウムは、窒化ケイ素の焼結促進剤として機
能し、また焼結後には粒界に高融点の結晶性化合物とし
て残存する。ここで、粒界に残存するYbを含む結晶性化
合物は、 AlN以外と共に主として形成されるものであ
る。The ytterbium oxide used as a sintering aid in the present invention functions as a sintering promoter for silicon nitride, and remains as a high melting point crystalline compound at the grain boundaries after sintering. Here, the crystalline compound containing Yb remaining at the grain boundary is mainly formed together with other than AlN.
【００１０】上記したYbを含む結晶性化合物は、高温雰
囲気に晒された際においても、原子の移動が少ないた
め、窒化ケイ素系焼結体の耐酸化特性の劣化が少ない。
例えば、酸化イットリウムを焼結助剤として用いた窒化
ケイ素系焼結体は、粒界にY-Si-Al-O-N 系の化合物が存
在し、この Y-Si-Al-O-N系化合物は高温雰囲気中では Y
が表面方向に移動することから、焼結体の耐酸化特性を
劣化させているものと考えられる。つまり、本発明によ
る窒化ケイ素系焼結体においては、上記したような粒界
成分の移動に伴う酸化が抑制されるため、良好な耐酸化
特性が高温雰囲気中においても維持される。The above-mentioned crystalline compound containing Yb has a small amount of migration of atoms even when exposed to a high temperature atmosphere, so that the oxidation resistance of the silicon nitride-based sintered body is less deteriorated.
For example, a silicon nitride-based sintered body that uses yttrium oxide as a sintering aid has a Y-Si-Al-ON-based compound at the grain boundaries, and this Y-Si-Al-ON-based compound is present in a high-temperature atmosphere. Inside Y
Is likely to deteriorate the oxidation resistance of the sintered body. That is, in the silicon nitride-based sintered body according to the present invention, since the oxidation due to the movement of grain boundary components as described above is suppressed, good oxidation resistance characteristics are maintained even in a high temperature atmosphere.
【００１１】このような酸化イッテルビウムの添加量
は、全組成物中の 1〜10重量％とし、特に好ましくは 3
〜10重量％の範囲である。酸化イッテルビウムの添加量
が 1重量％満では、焼結促進機能が十分に得られず、ま
た10重量％を超えると、相対的に母相の比率が低下する
ことから、焼結体本来の特性が得難くなるためである。
なお、酸化イッテルビウムの原料としては、加熱により
酸化物となるケイ化物、炭化物、ホウ化物等の化合物を
使用することも可能である。The amount of such ytterbium oxide added is 1 to 10% by weight of the total composition, and particularly preferably 3%.
Is in the range of up to 10% by weight. When the amount of ytterbium oxide added is less than 1% by weight, the sintering promoting function cannot be sufficiently obtained. Is difficult to obtain.
As the raw material of ytterbium oxide, it is also possible to use compounds such as silicides, carbides and borides which become oxides when heated.
【００１２】また、窒化アルミニウムは、酸化イッテル
ビウムによる焼結促進効果を補助し、窒化ケイ素の液相
焼結を促進すると共に、形成された液相の再結晶化に寄
与するものである。ただし、多すぎると焼結を阻害する
方向に働くため、その添加量は10重量％以下とする。ま
た、あまり少なくとも十分に液相を形成することが困難
となるため、 1重量％以上添加するものとする。窒化ア
ルミニウムのより好ましい添加量は、 3〜 6重量％の範
囲である。Aluminum nitride assists the sintering promotion effect of ytterbium oxide, promotes liquid phase sintering of silicon nitride, and contributes to recrystallization of the formed liquid phase. However, if it is too large, it tends to hinder the sintering, so the addition amount is 10% by weight or less. Further, it is difficult to form a liquid phase at least sufficiently, so 1% by weight or more is added. The more preferable amount of aluminum nitride added is in the range of 3 to 6% by weight.
【００１３】これらの焼結助剤として添加する成分は、
その合計量を全組成物中の 4重量％〜20重量％の範囲と
することが好ましい。この添加合計量が 4重量％未満で
は、液相焼結促進の効果が十分に得られず、また20重量
％を超えると窒化ケイ素本来の特性を損ねる可能性が大
きいためである。The components added as these sintering aids are
The total amount is preferably in the range of 4% by weight to 20% by weight in the total composition. If the total addition amount is less than 4% by weight, the effect of promoting liquid phase sintering cannot be sufficiently obtained, and if it exceeds 20% by weight, the original properties of silicon nitride are likely to be impaired.
【００１４】本発明の窒化ケイ素系焼結体は、上記した
各組成分を所定範囲内の比率で含む混合物をまず所要の
形状に成形し、不活性雰囲気中、1600℃〜1900℃程度の
温度で焼成することによって得られる。なお、この焼結
はいわゆる常圧焼結法によっても緻密質で耐酸化特性に
優れた窒化ケイ素系焼結体が得られるが、その他の焼結
法、例えば雰囲気加圧焼結法、ホットプレス法、熱間静
水圧焼結法（ＨＩＰ）等、またはこれらの組合せによっ
ても同様の性能を備えた焼結体が得られる。The silicon nitride-based sintered body of the present invention is formed into a desired shape by first forming a mixture containing the above-mentioned compositional components in a ratio within a predetermined range, and then in an inert atmosphere at a temperature of about 1600 ° C to 1900 ° C. It is obtained by firing at. In addition, although this sintering can obtain a dense and excellent oxidation resistance characteristic silicon nitride-based sintered body by a so-called atmospheric pressure sintering method, other sintering methods such as an atmosphere pressure sintering method and a hot press method are also available. Method, hot isostatic pressing (HIP), or the like, or a combination thereof, a sintered body having similar performance can be obtained.
【００１５】[0015]
【実施例】以下、本発明を実施例によって説明する。EXAMPLES The present invention will be described below with reference to examples.
【００１６】実施例１ 平均粒径 0.8μm のSi3 N 4 （α相95%)粉末に対し、平
均粒径 1.2μm のYb2O3 粉末 5重量％および平均粒径
1.0μm の AlN粉末 2重量％を配合し、ボ―ルミルにて
約24時間混合を行って原料粉末を調整した。次いで、こ
の原料粉末 100重量部に対してバインダを 5重量部添加
配合し、さらに十分に混合した後、プレス成形によって
長さ50mm×幅50mm×厚さ 7mmの板状成形体を作製した。Example 1 5% by weight of Yb 2 O 3 powder having an average particle diameter of 1.2 μm and an average particle diameter of Si 3 N 4 (95% α phase) powder having an average particle diameter of 0.8 μm
2% by weight of 1.0 μm AlN powder was mixed and mixed in a ball mill for about 24 hours to prepare a raw material powder. Next, 5 parts by weight of a binder was added to 100 parts by weight of this raw material powder, and the mixture was further thoroughly mixed. Then, a plate-shaped body having a length of 50 mm, a width of 50 mm and a thickness of 7 mm was produced by press molding.
【００１７】この後、上記成形体に窒素ガス雰囲気中に
て脱脂処理を施した後、窒素ガス雰囲気中において1750
℃× 4時間の条件で常圧焼結を行い、窒化ケイ素を主成
分とする焼結体を得た。Thereafter, the molded body is subjected to a degreasing treatment in a nitrogen gas atmosphere and then subjected to 1750 in a nitrogen gas atmosphere.
Pressureless sintering was performed under the condition of ° C x 4 hours to obtain a sintered body containing silicon nitride as a main component.
【００１８】このようにして得た窒化ケイ素系焼結体の
構成相をＸ線回折により分析したところ、母相の 86%が
β- Si3 N 4 相であり、残りの 14%はα′- Si3 N 4 相
であった。また、これらSi3 N 4 結晶粒の粒界には、Yb
を含む結晶性化合物が存在していた。When the constituent phases of the silicon nitride-based sintered body thus obtained were analyzed by X-ray diffraction, 86% of the mother phase was β-Si 3 N 4 phase and the remaining 14% was α ′. -Si 3 N 4 phase. Moreover, Yb is contained in the grain boundaries of these Si 3 N 4 crystal grains.
There was a crystalline compound containing.
【００１９】また、本発明との比較として、上記実施例
１で使用したSi3 N 4 （α相95%)粉末に、 Y2 O3 粉末
（平均粒径 1.0μm ）を 5重量％、 AlN粉末を 4重量％
で添加した原料粉末を用いて、実施例１と同一条件で焼
結体を作製した。As a comparison with the present invention, the Si 3 N 4 (α phase 95%) powder used in Example 1 above was mixed with 5% by weight of Y 2 O 3 powder (average particle size 1.0 μm) and AlN. 4% by weight of powder
Using the raw material powder added in step 2, a sintered body was produced under the same conditions as in Example 1.
【００２０】これら実施例および比較例による窒化ケイ
素系焼結体の常温および1250℃における 3点曲げ強度を
測定した。また、これら焼結体に大気中にて1400℃× 1
00時間の熱処理を施し、この処理後の試料単位面積当り
の酸化増量（増加重量）を求めた。さらに、この熱処理
後の 3点曲げ強度を測定した。これらの結果を表１に示
す。Three-point bending strength of the silicon nitride-based sintered bodies according to these examples and comparative examples at room temperature and 1250 ° C. was measured. In addition, these sintered bodies were subjected to 1400 ° C x 1 in air.
The sample was subjected to a heat treatment for 00 hours, and the amount of increased oxidation (increased weight) per unit area of the sample after this treatment was determined. Furthermore, the three-point bending strength after this heat treatment was measured. The results are shown in Table 1.
【００２１】[0021]
【表１】 表１に示す測定結果から明らかなように、実施例１によ
る窒化ケイ素系焼結体は、 Y2 O3 を焼結助剤として使
用した比較例の焼結体に比べ、強度の値自体は若干劣る
ものの、耐酸化性に優れ、熱処理後における強度は比較
例の焼結体より大幅に上回るものであった。[Table 1] As is clear from the measurement results shown in Table 1, the silicon nitride-based sintered body according to Example 1 has a higher strength value than the sintered body of Comparative Example using Y 2 O 3 as a sintering aid. Although slightly inferior, the oxidation resistance was excellent and the strength after heat treatment was significantly higher than that of the sintered body of Comparative Example.
【００２２】実施例２〜５ 実施例１で使用したYb2 O3 粉末および AlN粉末をそれ
ぞれ表２に示す組成比でSi3 N 4 粉末に混合し、これら
原料粉末を用いて実施例１と同一条件で焼結を行い、そ
れぞれ窒化ケイ素焼結体を作製した。Examples 2 to 5 The Yb 2 O 3 powder and AlN powder used in Example 1 were mixed with Si 3 N 4 powder in the composition ratios shown in Table 2, respectively, and these raw material powders were used to obtain Example 1 and Sintering was performed under the same conditions to produce silicon nitride sintered bodies.
【００２３】このようにして得た各窒化ケイ素焼結体の
特性を実施例１と同様にして測定した。その結果も併せ
て表２に示す。The characteristics of each silicon nitride sintered body thus obtained were measured in the same manner as in Example 1. The results are also shown in Table 2.
【００２４】[0024]
【表２】 [Table 2]
【００２５】[0025]
【発明の効果】以上説明したように、本発明の窒化ケイ
素系焼結体によれば、窒化ケイ素が本来有する強度特性
を維持した上で、優れた耐酸化特性が得られる。よっ
て、各種高温雰囲気下で使用される構造用材料に好適な
セラミックス系材料を提供することが可能となる。As described above, according to the silicon nitride-based sintered body of the present invention, excellent oxidation resistance can be obtained while maintaining the original strength characteristics of silicon nitride. Therefore, it becomes possible to provide a ceramic material suitable for a structural material used under various high temperature atmospheres.
【００２６】[0026]
Claims (2)
ルビウムを 1重量％〜10重量％および窒化アルミニウム
を 1重量％〜10重量％含み、残部が実質的に窒化ケイ素
からなる混合物を成形、焼成してなることを特徴とする
窒化ケイ素系焼結体。1. A mixture containing at least 1% by weight to 10% by weight of ytterbium oxide and 1% by weight to 10% by weight of aluminum nitride as a sintering aid, and the mixture consisting essentially of silicon nitride is molded and fired. A silicon nitride-based sintered body characterized in that
はα′- Si3 N 4 からなり、前記焼結体母相の結晶粒界
にYbを含む結晶性化合物が少なくとも存在することを特
徴とする窒化ケイ素系焼結体。2. A sintered body mother phase is composed of β-Si 3 N 4 and / or α′-Si 3 N 4 , and at least a crystalline compound containing Yb is present in a grain boundary of the sintered body mother phase. A silicon nitride-based sintered body characterized by comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01498892A JP3290685B2 (en) | 1992-01-30 | 1992-01-30 | Silicon nitride based sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01498892A JP3290685B2 (en) | 1992-01-30 | 1992-01-30 | Silicon nitride based sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05208870A true JPH05208870A (en) | 1993-08-20 |
| JP3290685B2 JP3290685B2 (en) | 2002-06-10 |
Family
ID=11876333
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP01498892A Expired - Lifetime JP3290685B2 (en) | 1992-01-30 | 1992-01-30 | Silicon nitride based sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3290685B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6693054B1 (en) | 2000-11-28 | 2004-02-17 | Kennametal Inc. | Method of making SiAlON containing ytterbium |
| US7049256B2 (en) | 2000-11-28 | 2006-05-23 | Kennametal Inc. | SiAlON containing ytterbium and method of making |
| US7094717B2 (en) | 2000-11-28 | 2006-08-22 | Kennametal Inc. | SiAlON containing ytterbium and method of making |
| US7138183B2 (en) | 2004-01-13 | 2006-11-21 | Central Research Institute Of Electric Power Industry | Environmental barrier coating material and coating structure and ceramic structure using the same |
-
1992
- 1992-01-30 JP JP01498892A patent/JP3290685B2/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6693054B1 (en) | 2000-11-28 | 2004-02-17 | Kennametal Inc. | Method of making SiAlON containing ytterbium |
| US6964933B2 (en) | 2000-11-28 | 2005-11-15 | Kennametal Inc. | SiAlON containing ytterbium and method of making |
| US7049256B2 (en) | 2000-11-28 | 2006-05-23 | Kennametal Inc. | SiAlON containing ytterbium and method of making |
| US7094717B2 (en) | 2000-11-28 | 2006-08-22 | Kennametal Inc. | SiAlON containing ytterbium and method of making |
| US7138183B2 (en) | 2004-01-13 | 2006-11-21 | Central Research Institute Of Electric Power Industry | Environmental barrier coating material and coating structure and ceramic structure using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3290685B2 (en) | 2002-06-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3501317B2 (en) | High thermal conductivity silicon nitride sintered body and insulating substrate made of silicon nitride sintered body | |
| JP2829229B2 (en) | Silicon nitride ceramic sintered body | |
| JPH05208870A (en) | Silicon nitride sintered product | |
| JP3208181B2 (en) | Silicon nitride based sintered body | |
| KR970009988B1 (en) | HIGH CORROSION - RESISTANT Ñß-SLALON SINTER AND PRODUCTION THEREOF | |
| JP2663028B2 (en) | Silicon nitride sintered body | |
| JP2736386B2 (en) | Silicon nitride sintered body | |
| JP3426823B2 (en) | Silicon nitride sintered body and method for producing the same | |
| JP3454994B2 (en) | Silicon nitride sintered body and method for producing the same | |
| JP3454993B2 (en) | Silicon nitride sintered body and method for producing the same | |
| JP3152790B2 (en) | Method for producing silicon nitride based sintered body | |
| JP2980342B2 (en) | Ceramic sintered body | |
| JP3034100B2 (en) | Silicon nitride sintered body and method for producing the same | |
| JP2001206774A (en) | Silicon nitride sintered compact | |
| JP2534213B2 (en) | Method for producing silicon nitride based sintered body | |
| JP3318466B2 (en) | Silicon nitride sintered body and method for producing the same | |
| JP3271123B2 (en) | Method for producing composite of silicon nitride and boron nitride | |
| JP3241215B2 (en) | Method for producing silicon nitride based sintered body | |
| JPH06287063A (en) | Silicon nitride ceramic | |
| JP3236739B2 (en) | Silicon nitride sintered body and method for producing the same | |
| JP3106208B2 (en) | Silicon nitride sintered body and method for producing the same | |
| JPH05238829A (en) | Sintered silicone nitride ceramic | |
| JP2687633B2 (en) | Method for producing silicon nitride sintered body | |
| JP2742621B2 (en) | High toughness silicon nitride sintered body | |
| JP3176203B2 (en) | Method for producing silicon nitride based sintered body |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20010619 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20020305 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080322 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090322 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100322 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100322 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110322 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120322 Year of fee payment: 10 |
|
| EXPY | Cancellation because of completion of term |