JPH07115936B2 - Method for manufacturing silicon nitride sintered body - Google Patents
Method for manufacturing silicon nitride sintered bodyInfo
- Publication number
- JPH07115936B2 JPH07115936B2 JP61297536A JP29753686A JPH07115936B2 JP H07115936 B2 JPH07115936 B2 JP H07115936B2 JP 61297536 A JP61297536 A JP 61297536A JP 29753686 A JP29753686 A JP 29753686A JP H07115936 B2 JPH07115936 B2 JP H07115936B2
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- Prior art keywords
- silicon nitride
- weight
- sintered body
- sintering
- parts
- Prior art date
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Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は耐熱性に優れた窒化けい素焼結体、更に詳しく
は、α・Si3N4を含有する高温強度特性の優れた窒化け
い素焼結体の製造方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a silicon nitride sintered body having excellent heat resistance, and more specifically, a silicon nitride sintered body containing α · Si 3 N 4 and having excellent high-temperature strength characteristics. The present invention relates to a method for manufacturing a bound body.
（従来の技術） 窒化けい素は金属に比べて耐熱性に優れているために、
高温構造部材に適している。また、この窒化けい素焼結
体を製造する場合には窒化けい素自身が共有結合性が大
きく、しかも難焼結性物質であるため、Al2O3や基土類
酸化物等の各種酸化物を単独もしくは数種類組合せて添
加し、緻密な焼結体を得ることが知られている（特公昭
48−7486号公報、特公昭49−21091号公報）。又、なる
べくα・Si3N4の割合の多い窒化けい素粉末を用いるこ
とで、高温焼結時にまわりの焼結助剤の影響をうけて、
窒化けい素はα・Si3N4からβ・Si3N4へ転移し、この転
移により緻密化及び柱状晶の形成が生じ、柱状晶のから
み合つた高強度の焼結体が得られると考えられている。
しかし、焼結助剤に酸化物を使用した場合、酸化物は窒
化けい素の緻密化・柱状晶形成に寄与した後粒界相を形
成し、高温状態で粒界相の軟化が生じ、高温での機械的
特性を悪化させてしまう欠点がある。(Prior Art) Since silicon nitride is superior in heat resistance to metals,
Suitable for high temperature structural members. Further, when producing this silicon nitride sintered body, since silicon nitride itself has a large covalent bond and is also a hardly sinterable substance, various oxides such as Al 2 O 3 and basic earth oxides are used. It is known that a dense sintered body can be obtained by adding singly or in combination of several kinds (Japanese Patent Publication Sho
48-7486, Japanese Patent Publication No. 49-21091). In addition, by using silicon nitride powder with a high proportion of α ・ Si 3 N 4 as much as possible, the influence of surrounding sintering aids during high temperature sintering,
Silicon nitride undergoes a transition from α ・ Si 3 N 4 to β ・ Si 3 N 4 , and this transition causes densification and formation of columnar crystals, resulting in a high-strength sintered body entangled with columnar crystals. It is considered.
However, when an oxide is used as a sintering aid, the oxide forms a grain boundary phase after contributing to the densification of silicon nitride and formation of columnar crystals, and the grain boundary phase softens at high temperature, resulting in high temperature. However, there is a drawback that the mechanical properties at the point of time are deteriorated.
（発明が解決しようとする問題点） 本発明者は、高温強度に優れ、ガスタービンやデイーゼ
ルのエンジン部材に好適な窒化けい素焼結体を得ること
を目的として種々検討した結果、かかる目的を達成する
ためには、窒化けい素の結晶組織を制御して焼結体を緻
密化すると共にα・Si3N4を含有せしめればよいことを
見い出し本発明を完成した。(Problems to be Solved by the Invention) As a result of various investigations by the present inventor, the inventors achieved various objectives as a result of various studies aimed at obtaining a silicon nitride sintered body excellent in high-temperature strength and suitable for an engine member of a gas turbine or a diesel engine. In order to achieve this, the inventors have found that it is sufficient to control the crystal structure of silicon nitride to densify the sintered body and to contain α.Si 3 N 4 and have completed the present invention.
（問題点を解決するための手段） すなわち、本発明は、比表面積５〜12m2/g、α・Si3N4
の割合が90重量％以上、固溶酸素含有量1.5重量％以下
の窒化けい素粉末100重量部と、MgO0.1〜５重量部と、A
l2O3,SiO2及びIII a族元素酸化物から選ばれた１種以上
0.1〜10重量部の混合粉末を成形した後、常圧の非酸化
性雰囲気下1,450〜1,800℃の温度でα・Si3N4が30重量
％以下（０は含まず）残存する時間焼結することを特徴
とする窒化けい素焼結体の製造方法である。(Means for Solving Problems) That is, according to the present invention, the specific surface area is 5 to 12 m 2 / g, α · Si 3 N 4
Of 90% by weight or more and the dissolved oxygen content of 1.5% by weight or less, 100 parts by weight of silicon nitride powder, 0.1 to 5 parts by weight of MgO, and A
One or more selected from l 2 O 3 , SiO 2 and Group IIIa element oxides
After molding 0.1 to 10 parts by weight of mixed powder, sintering at a temperature of 1,450 to 1,800 ° C under normal pressure in a non-oxidizing atmosphere for 30 minutes by weight or less of α ・ Si 3 N 4 (not including 0). And a method for manufacturing a silicon nitride sintered body.
以下、更に詳しく本発明を説明する。Hereinafter, the present invention will be described in more detail.
まず、本発明の窒化けい素焼結体の製造方法によって製
造される窒化けい素焼結体（以下焼結体という）につい
て述べる。従来、焼結によりα・Si3N4をすべてβ・Si3
N4へ転移させ、緻密で柱状晶のからみ合つた高強度焼結
体を得ていたが、この焼結体はその粒界に高温状態で機
械的特性を低下させる粒界相が生成するために、高温強
度特性の改善には、更に粒界相を減らす、融点の低い化
合物の生成を防ぐ、粒界相をガラス相から結晶相に変え
る、等多くの改良が必要であつた。First, a silicon nitride sintered body (hereinafter referred to as a sintered body) manufactured by the method for manufacturing a silicon nitride sintered body of the present invention will be described. Conventionally, all α ・ Si 3 N 4 was converted to β ・ Si 3 by sintering.
We obtained a high-strength sintered body that was densified and entangled with columnar crystals after it was transformed to N 4 because this sintered body has a grain boundary phase that deteriorates mechanical properties at high temperatures in its grain boundaries. In addition, in order to improve the high temperature strength properties, it was necessary to further reduce the grain boundary phase, prevent the formation of compounds having a low melting point, change the grain boundary phase from the glass phase to the crystalline phase, and so on.
本発明の製造方法によって得られた焼結体は、α・Si3N
4からβ・Si3N4への転移を極力押さえて緻密化させるこ
とを特徴とし、柱状晶のからみあつた結晶構造が認めら
れないものの、高温強度特性に優れた焼結体である。こ
れを図面で説明すると、第１図は本発明の製造方法によ
って得られた焼結体の、また、第２図は従来の焼結方法
で得られた焼結体の結晶構造を示す倍率5000倍のSEM
（走査型電子顕微鏡）写真であるが、第２図では結晶粒
が大きく柱状晶が多く認められているのに対し、第１図
では粒成長および柱状晶の発達はさほど認められないも
のである。The sintered body obtained by the manufacturing method of the present invention is α · Si 3 N
It is a sintered body that is characterized by suppressing the transition from 4 to β · Si 3 N 4 as much as possible to make it dense, and has no entangled crystal structure of columnar crystals, but has excellent high-temperature strength characteristics. This will be explained with reference to the drawings. FIG. 1 shows a crystal structure of a sintered body obtained by the manufacturing method of the present invention, and FIG. 2 shows a crystal structure of a sintered body obtained by a conventional sintering method. Double SEM
(Scanning electron microscope) Photographs showing large crystal grains and many columnar crystals in FIG. 2, whereas grain growth and columnar crystal development are not so noticeable in FIG. .
窒化けい素焼結体のα・Si3N4の分析法は、窒化けい素
粉末のα・Si3N4の割合の分析方法と同じである。すな
わち、Ｘ線回折により測定される α・Si3N4の（102）面，（210）面とβ・Si3N4の（10
1）面，（210）面の各回折ピークの高さの比から求め
る。Ｘ線回折図の一例を第３図（実施例１）と第４図
（比較例１）に示す。The method for analyzing α · Si 3 N 4 in the silicon nitride sintered body is the same as the method for analyzing the ratio of α · Si 3 N 4 in the silicon nitride powder. That is, (102) plane of α · Si 3 N 4 which is measured by X-ray diffraction, (210) plane and the β · Si 3 N 4 (10
It is obtained from the ratio of the heights of the diffraction peaks of the 1) and (210) planes. An example of the X-ray diffraction diagram is shown in FIG. 3 (Example 1) and FIG. 4 (Comparative Example 1).
本発明においては、α・Si3N4は30重量％以下（０は含
まず）で含んでいることが必要であり、30重量％をこえ
ると極端に焼結体の緻密性が低下し、高温強度が小さく
なる。α・Si3N4含有量が30重量％以下であれば、その
量の差による高温強度特性の違いがほとんど認められな
い。In the present invention, it is necessary that α.Si 3 N 4 is contained in an amount of 30% by weight or less (0 is not included), and if it exceeds 30% by weight, the compactness of the sintered body is extremely lowered, High temperature strength decreases. When the content of α · Si 3 N 4 is 30% by weight or less, there is almost no difference in high temperature strength characteristics due to the difference in the content.
また、本発明の製造方法によって得られた焼結体の相対
密度（理論密度に対する絶対値）は95％以上となり、例
えばガスタービンやディーゼル等のエンジン部材に要求
される1200℃における熱間強度800MPa以上のものが得ら
れる。このように、本発明によって製造された焼結体が
高温強度に優れる理由は定かではないが、焼結助剤成分
が焼結体全体に均一に分布していることに加えて、微量
の酸素がα・Si3N4に固溶するので従来のように顕著な
粒界相がないことによるものと考えている。Further, the relative density (absolute value with respect to the theoretical density) of the sintered body obtained by the production method of the present invention is 95% or more, and for example, the hot strength at 1200 ° C. required for an engine member such as a gas turbine or diesel is 800 MPa. The above is obtained. Thus, the reason why the sintered body produced by the present invention is excellent in high temperature strength is not clear, but in addition to the fact that the sintering aid component is evenly distributed throughout the sintered body, a small amount of oxygen It is believed that this is because there is no remarkable grain boundary phase as in the past because it dissolves in α · Si 3 N 4 .
以上のような焼結体は、厳選された窒化けい素粉末を原
料とし、これに焼結助剤としてMgOと、Al2O3,SiO及びII
I a族元素酸化物から選ばれた１種以上とを併用し、常
圧の非酸化性雰囲気下において適切な温度と時間で焼結
することによって製造することができる。以下、本発明
の製造方法について説明する。The sintered body as described above is made of a carefully selected silicon nitride powder as a raw material, and MgO, Al 2 O 3 , SiO and II
It can be produced by using in combination with at least one selected from Group Ia element oxides and sintering at an appropriate temperature and time under a normal pressure non-oxidizing atmosphere. Hereinafter, the manufacturing method of the present invention will be described.
α・Si3N4からβ・Si3N4への転移は、高温で、しかもα
・Si3N4粒子の周囲に液相やβ・Si3N4粒子が存在する場
合に進行するので、α・Si3N4からβ・Si3N4への転移を
極力押さえるためには、原料窒化けい素粉末としては、
比表面積５〜12m2/g、α・Si3N4の割合が90重量％以
上、固溶酸素含有量1.5重量％以下の条件が必要であ
る。The transition from α ・ Si 3 N 4 to β ・ Si 3 N 4 is
Since · Si 3 N 4 liquid phase and β · Si 3 N 4 particles around the particles proceeds if present, in order to minimize suppress metastasis to β · Si 3 N 4 from α · Si 3 N 4 is As the raw material silicon nitride powder,
It is necessary that the specific surface area is 5 to 12 m 2 / g, the ratio of α · Si 3 N 4 is 90% by weight or more, and the solid solution oxygen content is 1.5% by weight or less.
粉末の比表面積が12m2/gを超えると、窒化けい素分子と
周囲液相との接触が多くなり、α・Si3N4からβ・Si3N4
への転移が促進されるので好ましくない。一方、比表面
積が5m2/g未満では焼結性が悪くなる。When the specific surface area of the powder exceeds 12 m 2 / g, the contact between the silicon nitride molecules and the surrounding liquid phase increases, and α ・ Si 3 N 4 to β ・ Si 3 N 4
It is not preferable because the transition to On the other hand, if the specific surface area is less than 5 m 2 / g, the sinterability will be poor.
また、窒化けい素粉末に含まれる固溶酸素が1.5重量％
をこえるとα・Si3N4からβ・Si3N4への転移が進行し高
温強度に優れた焼結体を製造することができない。ここ
で固溶酸素とは、本質的には、その存在によりSi2ON2構
造やSi3N4粒子表面に不可避的に存在するSi酸化物構造
となる酸素ではなく、あくまでもSi3N4粒子内部に固溶
された酸素のことであり、例えば次のようにして測定さ
れる酸素である。すなわち、100mlのビーカーに、ふつ
酸水溶液（HF分:5重量％）50mlと・Si3N4粉末1gを入
れ、室温で20分間撹拌（マグネチツクスターラーの回転
数:300〜600rpm）した真空濾過し、得られた固形物を温
度100〜150℃の乾燥器で２時間乾燥した後その酸素量を
分析計、例えばLECO社製O/N同時分析計「TC−136型」に
より定量する。なお、上記したマグネチツクスターラー
の回転数と乾燥温度の条件範囲内であれば、固溶酸素量
の測定値には大きな変化はない。In addition, solid solution oxygen contained in silicon nitride powder is 1.5% by weight.
Above this, the transition from α · Si 3 N 4 to β · Si 3 N 4 progresses, making it impossible to manufacture a sintered body with excellent high-temperature strength. Here, the solid solution oxygen is not essentially oxygen that has a Si 2 ON 2 structure or a Si oxide structure that is unavoidably present on the surface of the Si 3 N 4 particles due to its presence, and is only a Si 3 N 4 particle. It refers to oxygen dissolved inside, and is, for example, oxygen measured as follows. That is, 50 ml of hydrofluoric acid aqueous solution (HF content: 5% by weight) and 1 g of Si 3 N 4 powder were placed in a 100 ml beaker and vacuum filtered with stirring at room temperature for 20 minutes (rotation speed of magnetic stirrer: 300 to 600 rpm). Then, the obtained solid is dried in a dryer at a temperature of 100 to 150 ° C. for 2 hours, and then the amount of oxygen is quantified by an analyzer, for example, LECO O / N simultaneous analyzer “TC-136 type”. The measured value of the amount of dissolved oxygen does not change significantly within the condition range of the rotation speed of the magnetic stirrer and the drying temperature.
また、窒化けい素粉末のα・Si3N4の割合が90重量％未
満では、α・Si3N4からβ・Si3N4への転移が促進され、
焼結体にα・Si3N4が残りにくくなる。好ましいα・Si3
N4の割合は95重量％以上である。If the proportion of α ・ Si 3 N 4 in the silicon nitride powder is less than 90% by weight, the transition from α ・ Si 3 N 4 to β ・ Si 3 N 4 is promoted,
It becomes difficult for α ・ Si 3 N 4 to remain in the sintered body. Preferred α ・ Si 3
The proportion of N 4 is 95% by weight or more.
次に焼結助剤について説明する。本発明においては、Mg
Oと、Al2O3,SiO2及びIII a族元素酸化物から選ばれた１
種以上とを併用する。Next, the sintering aid will be described. In the present invention, Mg
1 selected from O and Al 2 O 3 , SiO 2 and Group IIIa element oxides
Use together with seeds or more.
MgOの添加量は、前記窒化けい素粉末100重量部に対して
0.1〜５重量部である。0.1重量部未満では緻密化が不充
分であり、また、５重量部を超えると高温強度特性が低
下する。MgOを添加すると、1,500℃付近の焼結温度で焼
結体からMgO結晶のＸ線回折ピークが消滅する。この現
象は、MgO結晶が1,500℃付近から一部液相となつたため
と考えられ、それが焼結体の緻密化に寄与している、す
なわち、低温焼結が可能となり、α・Si3N4からβ・Si3
N4への転移が抑制されて緻密化が進行したものと考えて
いる。The amount of MgO added is 100 parts by weight of the silicon nitride powder.
It is 0.1 to 5 parts by weight. If it is less than 0.1 part by weight, the densification will be insufficient, and if it exceeds 5 parts by weight, the high-temperature strength properties will deteriorate. When MgO is added, the X-ray diffraction peak of the MgO crystal disappears from the sintered body at a sintering temperature near 1,500 ° C. This phenomenon is considered to be due to the fact that the MgO crystal partially became a liquid phase from around 1,500 ° C, which contributes to the densification of the sintered body, that is, low temperature sintering becomes possible, and α ・ Si 3 N 4 to β ・ Si 3
It is considered that the transition to N 4 was suppressed and the densification proceeded.
MgO以外の焼結助剤を用いると、焼結体の緻密化は生じ
るが、MgOを用いる場合に比べて焼結に高温かつ長時間
を要し、焼結体にα・Si3N4を残存させることが難しく
なる。If a sintering aid other than MgO is used, densification of the sintered body will occur, but sintering will require higher temperature and a longer time than in the case of using MgO, and α ・ Si 3 N 4 will be added to the sintered body. It becomes difficult to make it remain.
しかし、以上のMgO単独添加では、緻密化が充分でない
ため、本発明では、Al2O3,SiO2及びIII a族元素酸化物
から選ばれた１種以上を0.1〜10重量部添加する。0.1重
量部未満では緻密化の改善効果は小さく、また、10重量
部を超えると高温強度特性が低下する。III a族元素と
しては、Y,Ce,Nd等をあげることができる。MgOとAl2O3
又はSiO2とを別々に添加するかわりに両者の化合物、例
えばMgAl2O4,Mg2SiO4等を添加することも本発明の範囲
に含まれる。MgOと、Al2O3,SiO2及びIII a族元素酸化物
から選ばれた１種以上は、両者の合結として５〜15重量
部添加するのが好適である。However, since the densification is not sufficient when the above MgO alone is added, 0.1 to 10 parts by weight of one or more selected from Al 2 O 3 , SiO 2 and Group IIIa element oxides is added in the present invention. If it is less than 0.1 part by weight, the effect of improving the densification is small, and if it exceeds 10 parts by weight, the high temperature strength properties are deteriorated. Examples of group IIIa elements include Y, Ce, Nd, and the like. MgO and Al 2 O 3
Alternatively, it is within the scope of the present invention to add both compounds such as MgAl 2 O 4 and Mg 2 SiO 4 instead of separately adding SiO 2 . It is preferable to add 5 to 15 parts by weight of MgO and one or more selected from Al 2 O 3 , SiO 2 and Group IIIa element oxides as a combination of the two.
次いで、上記の窒化けい素粉末と焼結助剤との混合物を
成形し非酸化性雰囲気下1,450〜1,800℃の温度で、か
つ、α・Si3N4が30重量％以下（０は含まず）残存する
時間で焼結する。焼結温度が1,450℃未満では緻密化不
十分であり、また、1,800℃を超えると緻密化は進むが
窒化けい素粉末はすべてβ・Si3N4に転移してしまうの
で高温強度が低下する。1,450℃と1,800℃との間でも低
温側では長時間の焼結により緻密化し、かつα・Si3N4
が残るが、高温側では短時間にしないとα・Si3N4が残
らない。従つて、焼結温度を上げる場合には焼結時間を
短かくする必要がある。本発明で採用される焼結方法は
常圧焼結であり、それによって窒化けい素焼結体の複雑
形状品、大型品を製造できるという利点がある。Then, a mixture of the above-mentioned silicon nitride powder and a sintering aid is molded at a temperature of 1,450 to 1,800 ° C. in a non-oxidizing atmosphere, and α · Si 3 N 4 is 30 wt% or less (0 is not included. ) Sinter for the remaining time. If the sintering temperature is less than 1,450 ° C, the densification is insufficient, and if it exceeds 1,800 ° C, the densification progresses, but the silicon nitride powder is transformed into β ・ Si 3 N 4 and the high temperature strength decreases. . Even between 1450 ° C and 1800 ° C, it densifies due to long-term sintering on the low temperature side, and α ・ Si 3 N 4
However, α ・ Si 3 N 4 does not remain on the high temperature side unless the time is short. Therefore, when raising the sintering temperature, it is necessary to shorten the sintering time. The sintering method employed in the present invention is pressureless sintering, which has an advantage that a silicon nitride sintered body having a complicated shape or a large size can be manufactured.
（実施例） 次に、実施例及び比較例をあげてさらに具体的に本発明
を説明する。(Example) Next, the present invention will be described more specifically with reference to Examples and Comparative Examples.
実施例１〜5,比較例１〜８ 第１表に示す原料窒化けい素粉末100重量部、MgO3.3重
量部、Al2O32.2重量部及びY2O35.6重量部に1,1,1−トリ
クロルエタンを加えボールミルで４時間湿式混合し、乾
燥後、100kg/cm2の成形圧で６×10×60mmの形状に金型
成形後2,000kg/cm2の成形圧でCIP成形した。この成形体
をカーボンルツボにセツトし、第２表に示す条件で焼結
した。焼結は窒素雰囲気下の常圧焼結である。Examples 1-5, Comparative Examples 1-8 100 parts by weight of raw material silicon nitride powder shown in Table 1, 3.3 parts by weight of MgO, 2.2 parts by weight of Al 2 O 3 and 5.6 parts by weight of Y 2 O 3 are 1,1 parts by weight. 1,1-Trichloroethane was added, wet-mixed in a ball mill for 4 hours, dried, and then molded with a molding pressure of 100 kg / cm 2 into a shape of 6 × 10 × 60 mm, and then CIP molded with a molding pressure of 2,000 kg / cm 2 . . This compact was set in a carbon crucible and sintered under the conditions shown in Table 2. Sintering is pressureless sintering in a nitrogen atmosphere.
以上のようにして得られた焼結体について、JIS R2205
に準拠した相対密度、Ｘ線回折図により、α・Si3N4の
（102）面、（210）面，β・Si3N4の（101）面，（21
0）面の回折ピーク強度比 〔α（102）＋α（210）／α（102）＋α（210） ＋β（101）＋β（210）〕 から算出したα率、及びJIS R1601に準拠した温度1,200
℃における３点曲げ強度を測定した。 Regarding the sintered body obtained as described above, JIS R2205
Based on the relative density and X-ray diffraction pattern in accordance with, the α ・ Si 3 N 4 (102) plane, (210) plane, β ・ Si 3 N 4 (101) plane, (21
0) plane diffraction peak intensity ratio [α (102) + α (210) / α (102) + α (210) + β (101) + β (210)] α ratio and temperature of 1,200 according to JIS R1601
Three-point bending strength at ° C was measured.
それらの結果を第２表に示す。The results are shown in Table 2.
第２表から、本発明に係る窒化けい素粉末A,B及びＣを
用い、しかもα・Si3N430％以下に残存させるように焼
結したものは、相対密度が95％以上で、かつ、800MPa以
上の高温強度をもち、特にＡ粉末が最良結果をもたらす
ことがわかる。It can be seen from Table 2 that the silicon nitride powders A, B and C according to the present invention, which were sintered so that α · Si 3 N 4 remained at 30% or less, had a relative density of 95% or more, Also, it is understood that the powder A has the high temperature strength of 800 MPa or more, and the powder A gives the best results.
なお、実施例１と比較例１の焼結体について、SEM写真
（倍率5000倍）を第１図と第２図に、Ｘ線回折を第３図
と第４図に示した。 SEM photographs (magnification: 5000 times) of the sintered bodies of Example 1 and Comparative Example 1 are shown in FIGS. 1 and 2, and X-ray diffraction is shown in FIGS. 3 and 4.
実施例６〜12 比較例９〜17 窒化けい素粉末Ａを用い、第３表に示す条件で焼結体を
製造した。第３表から、本発明の実施例は比較例に比べ
て高温強度に優れていることがわかる。なお、実施例7,
8及び比較例15はHIP焼結である。Examples 6 to 12 Comparative Examples 9 to 17 Using silicon nitride powder A, sintered bodies were produced under the conditions shown in Table 3. From Table 3, it can be seen that the examples of the present invention are superior in high temperature strength to the comparative examples. In addition, Example 7,
8 and Comparative Example 15 are HIP sintering.
（発明の効果） 本発明によれば、1,200℃における熱間強度が800MPa以
上を有する窒化けい素焼結体を得ることができる。 (Effect of the Invention) According to the present invention, a silicon nitride sintered body having a hot strength at 1,200 ° C. of 800 MPa or more can be obtained.
第１図は実施例１、第２図は比較例１によつて得られた
窒化けい素焼結体の結晶構造を示すSEM（走査型電子顕
微鏡）写真である。第３図及び第４図は、それぞれ実施
例１及び比較例１によつて得られた窒化けい素焼結体の
Ｘ線回折図である。FIG. 1 is an SEM (scanning electron microscope) photograph showing the crystal structure of a silicon nitride sintered body obtained in Example 1 and FIG. 2 is in Comparative Example 1. 3 and 4 are X-ray diffraction diagrams of the silicon nitride sintered bodies obtained in Example 1 and Comparative Example 1, respectively.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 １０２ Ｃ １０２ Ｄ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI technical display location 102 C 102 D
Claims (2)
0重量％以上、固溶酸素含有量1.5重量％以下の窒化けい
素粉末100重量部と、MgO0.1〜５重量部と、Al2O3,SiO2
及びIIIa族元素酸化物から選ばれた１種以上0.1〜10重
量部の混合粉末を成形した後、常圧の非酸化性雰囲気下
1,450〜1,800℃の温度でα・Si3N4が30重量％以下（０
は含まず）残存する時間焼結することを特徴とする窒化
けい素焼結体の製造方法。1. A specific surface area of 5 to 12 m 2 / g and a proportion of α · Si 3 N 4 of 9
100 parts by weight of silicon nitride powder having a solid solution oxygen content of 0% by weight or more and 1.5% by weight or less, MgO 0.1 to 5 parts by weight, Al 2 O 3 , SiO 2
And 0.1 to 10 parts by weight of mixed powder of at least one selected from Group IIIa element oxides, and then molding under a non-oxidizing atmosphere under normal pressure.
Α ・ Si 3 N 4 is 30 wt% or less (0
The method for producing a silicon nitride sintered body is characterized by performing sintering for the remaining time.
量％以上であることを特徴とする特許請求の範囲第１項
記載の窒化けい素焼結体の製造方法。2. The method for producing a silicon nitride sintered body according to claim 1, wherein the proportion of α.Si 3 N 4 in the silicon nitride powder is 95% by weight or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61297536A JPH07115936B2 (en) | 1986-12-16 | 1986-12-16 | Method for manufacturing silicon nitride sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61297536A JPH07115936B2 (en) | 1986-12-16 | 1986-12-16 | Method for manufacturing silicon nitride sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63151682A JPS63151682A (en) | 1988-06-24 |
| JPH07115936B2 true JPH07115936B2 (en) | 1995-12-13 |
Family
ID=17847808
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61297536A Expired - Fee Related JPH07115936B2 (en) | 1986-12-16 | 1986-12-16 | Method for manufacturing silicon nitride sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07115936B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0774103B2 (en) * | 1986-12-27 | 1995-08-09 | 日本碍子株式会社 | High hardness silicon nitride sintered body |
| JP2736427B2 (en) * | 1988-12-27 | 1998-04-02 | 京セラ株式会社 | Silicon nitride sintered body and method for producing the same |
| JP2680127B2 (en) * | 1989-05-26 | 1997-11-19 | 日本碍子株式会社 | Si Lower 3 N Lower 4 Sintered body |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57123865A (en) * | 1981-01-27 | 1982-08-02 | Kobe Steel Ltd | Manufacture of high density silicon nitride sintered body |
| DE3475513D1 (en) * | 1984-09-19 | 1989-01-12 | Battelle Memorial Institute | Silicon nitride sintered bodies and a method for their production |
-
1986
- 1986-12-16 JP JP61297536A patent/JPH07115936B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63151682A (en) | 1988-06-24 |
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