JPS6265973A - Silicon carbide/graphite composite sintered body - Google Patents
Silicon carbide/graphite composite sintered bodyInfo
- Publication number
- JPS6265973A JPS6265973A JP61096399A JP9639986A JPS6265973A JP S6265973 A JPS6265973 A JP S6265973A JP 61096399 A JP61096399 A JP 61096399A JP 9639986 A JP9639986 A JP 9639986A JP S6265973 A JPS6265973 A JP S6265973A
- Authority
- JP
- Japan
- Prior art keywords
- sintered body
- silicon carbide
- graphite
- carbon black
- added
- 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.)
- Pending
Links
Landscapes
- Ceramic Products (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
本発明は高密度、高強度の炭化珪素・黒鉛複合焼結体の
製造方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a high-density, high-strength silicon carbide/graphite composite sintered body.
炭化珪素は極めて優れた化学的・物理的性質を有してい
るため、摺動材料、高温構造材料ないしは耐食性材料と
して注目されている。Silicon carbide has extremely excellent chemical and physical properties, so it is attracting attention as a sliding material, a high-temperature structural material, or a corrosion-resistant material.
例えばメカニカルシールリングや、プランジャー、軸受
、その他サンドブラストノズル、タペット又は電波吸収
体などとして数多、利用が可能であり、有用な材料であ
る。For example, it is a useful material that can be used in many applications such as mechanical seal rings, plungers, bearings, sandblasting nozzles, tappets, and radio wave absorbers.
炭化珪素焼結体の製造方法としては一般に反応焼結法、
ホットプレス法さらには無加圧、すなわち常圧焼結法な
どが知られ、その中で常圧焼結法の採用は最も有利であ
るが、炭化珪素は元来、難焼結性の材料であるため無加
圧下で充分に焼結させることは従来困難であるとされて
来た。Generally, methods for manufacturing silicon carbide sintered bodies include reaction sintering method,
The hot press method and the non-pressure sintering method are known, and among these methods, the pressureless sintering method is the most advantageous, but silicon carbide is originally a material that is difficult to sinter. Therefore, it has conventionally been considered difficult to sinter sufficiently without applying pressure.
しかし、最近各種の焼結助剤が開発され、前記の困難性
を克服する試みがなされているが、その代表的なものに
ついて、炭化珪素の結晶形削に見ると次の通りである。However, recently various sintering aids have been developed and attempts have been made to overcome the above-mentioned difficulties, and the following are typical examples of them for crystal shaping of silicon carbide.
即ち特開昭51−148712号公報によればα−5i
Cに0.15〜3.0重量%の硼素と0.5〜5.0%
炭素に相当する炭素質有機材料さらに1.0重量%まで
の付加的な炭素を混合成形し、次にこの成形体を少くと
も2.4g/cm’即ち理論密度の75%以上に焼結す
る方法が開示されている。That is, according to JP-A-51-148712, α-5i
C with 0.15-3.0% by weight of boron and 0.5-5.0%
A carbonaceous organic material corresponding to carbon is mixed and molded with up to 1.0% by weight of additional carbon, and the molded body is then sintered to a density of at least 2.4 g/cm' or 75% of the theoretical density. A method is disclosed.
一方特開昭50−78609号公報によればβ−5iC
と0.3〜3.0重量%の硼素に相当する量の硼素含有
化合物と0.1〜1.0重量%の炭素に相当する量の炭
素質添加剤とを混合成形し、少くとも理論密度の85%
を有する炭化珪素焼結体を得る方法が開示され、ここで
用いられている炭素質添加剤については、炭化珪素粉末
中に常に少量において存在しているか又は加熱に際して
粉末表面に吸着された酸素から形づくられるかのような
、シリカの還元や遊離珪素のゲッター(捕捉体)として
働き、1.0重量%以上添加した場合にその未反応過剰
炭素は永久的な細孔と酷似した作用をなし、最終的に到
達し得る密度と強度とを制限することが述べられている
。On the other hand, according to JP-A-50-78609, β-5iC
A boron-containing compound in an amount corresponding to 0.3 to 3.0 weight % of boron and a carbonaceous additive in an amount corresponding to 0.1 to 1.0 weight % of carbon are mixed and molded, and at least theoretically 85% of density
A method for obtaining a silicon carbide sintered body having It acts as if it were being formed, reducing silica and acting as a getter for free silicon, and when added at 1.0% by weight or more, the unreacted excess carbon acts very similar to permanent pores. It is stated that it limits the density and strength that can ultimately be reached.
このような従来方法によれば、炭化珪素の結晶形に拘わ
らず、ち密な焼結体を得るため2000℃以上の高温下
に於て焼結を行なうとき、β−5iCはα−5iCへの
変態に伴ない粒成長を起し、またα−3iCに於ては相
変態こそ起さないものの、やはり粒成長を起すことが、
微細でち密な焼結体を得る妨げとなる。According to such conventional methods, when sintering is carried out at a high temperature of 2000°C or higher to obtain a dense sintered body, β-5iC is converted into α-5iC, regardless of the crystal form of silicon carbide. Grain growth occurs with transformation, and although phase transformation does not occur in α-3iC, grain growth still occurs.
This hinders obtaining a fine and dense sintered body.
このような状況に鑑み種々研究の結果、発明者らはとく
にα炭化珪素の焼結に於て炭素がSiCの粒成長抑制作
用を持つことに着目して焼結助剤とは別にカーボンブラ
ックをα炭化珪素に対し1〜5体積%添加すれば、それ
が焼結時にはSiCの粒成長を抑制するだけでなく、焼
結後には第2相成分として微細で均一な状態でSiCの
粒界に予想外にも黒鉛として存在することになり、耐熱
衝撃性に優れた微細でち密な炭化珪素・黒鉛複合焼結体
を得ることに成功したものである。In view of this situation, as a result of various studies, the inventors focused on the fact that carbon has the effect of suppressing the grain growth of SiC in the sintering of α-silicon carbide, and developed carbon black in addition to the sintering aid. If 1 to 5% by volume is added to α-silicon carbide, it not only suppresses the grain growth of SiC during sintering, but also forms a fine and uniform second phase component at the grain boundaries of SiC after sintering. Unexpectedly, it was found to exist as graphite, and we succeeded in obtaining a fine and dense silicon carbide/graphite composite sintered body with excellent thermal shock resistance.
ここにカーボンブラックの如き無定形炭素の黒鉛化には
通常2500〜3000℃の高温加熱を要するにも拘わ
らず、α−5iCの焼結過程で上記黒鉛化を起すことが
発見されたのである。It was discovered that although graphitization of amorphous carbon such as carbon black normally requires high temperature heating of 2500 to 3000 DEG C., the above-mentioned graphitization occurs during the sintering process of α-5iC.
かくして得られる炭化珪素・黒鉛焼結体は、従来方法に
従い粒成長が余儀なくされたSiC焼結体と比べて、機
械的曲げ強度が20%以上上昇し、又熱衝撃温度が従来
のものに比べて90〜200℃も上昇することもたしか
められた。The silicon carbide/graphite sintered body obtained in this way has a mechanical bending strength that is more than 20% higher than that of a SiC sintered body in which grain growth is forced according to the conventional method, and a thermal shock temperature that is lower than that of the conventional one. It was also confirmed that the temperature rose by 90 to 200°C.
カーボンブラックの添加がαSiCの焼結中に黒鉛化を
もたらし炭化珪素・黒鉛複合焼結体中のSiC粒界に黒
鉛として存在することによって、従来の炭化珪素焼結体
に比べて動摩擦係数を20%以上も低下させ、しかも第
2相として粒界に存在する黒鉛は耐食性に優れているの
で、炭化珪素の有する化学的安定性を何ら劣化させるこ
とはない。The addition of carbon black causes graphitization during sintering of αSiC, and its presence as graphite at the SiC grain boundaries in the silicon carbide/graphite composite sintered body reduces the coefficient of dynamic friction by 20% compared to conventional silicon carbide sintered bodies. % or more, and since the graphite present in the grain boundaries as a second phase has excellent corrosion resistance, it does not deteriorate the chemical stability of silicon carbide in any way.
なおこのαSiC粒界中に第2相として存在する黒鉛の
平均粒径は3μm以下である。Note that the average grain size of graphite present as a second phase in this αSiC grain boundary is 3 μm or less.
この発明においてカーボンブラックを添加することの必
要性は次の通りである。The necessity of adding carbon black in this invention is as follows.
すなわちフェノール樹脂のような炭素質有機化合物をか
りにカーボンブラック添加の代替にもなるように増量し
た場合には、均一に分散混合することはできてもフェノ
ール樹脂自体にバインダーとしての性質があるので、た
とえばα炭化珪素に対し10重量%以上のように添加し
た場合には、任意の形状への成形などの生加工をするこ
とが困難になり、かつ添加したフェノール樹脂の約50
%は低温に於て飛散するために仮焼時に生密度が極端に
低下して、焼結性を妨げる。またカーボンブラックの代
りにはじめから黒鉛粉末を添加した場合はカーボンブラ
ック添加に比べて焼結中におけるαSiC粒子の粒成長
抑制作用を事実上体じないし、抗折強度の上昇も見られ
なかった。In other words, if a carbonaceous organic compound such as a phenolic resin is used in an increased amount to replace the addition of carbon black, even if it is possible to disperse and mix it uniformly, the phenolic resin itself has properties as a binder. For example, if it is added in an amount of 10% by weight or more based on α-silicon carbide, it becomes difficult to perform raw processing such as molding into an arbitrary shape, and approximately 50% of the added phenolic resin
% scatters at low temperatures, resulting in an extremely low green density during calcination, which impedes sinterability. Furthermore, when graphite powder was added from the beginning instead of carbon black, compared to the addition of carbon black, there was virtually no effect of suppressing the growth of αSiC particles during sintering, and no increase in bending strength was observed.
カーボンブラックの添加はα炭化珪素に対し1体積%よ
り少ないときは添加効果が不充分な一方、5体積%を上
堰るときはSiCの焼結性を低下させてSiCのすくれ
た緒特性を損う。When the addition of carbon black is less than 1% by volume based on α-silicon carbide, the addition effect is insufficient, while when it is added above 5% by volume, it reduces the sinterability of SiC and improves the sintering characteristics of SiC. damage.
なお本発明でα炭化珪素として1μm以下の粉末を用い
れば、最も効果的にち密な焼結体を得ることができ、と
くに1〜5体積%のカーボンブラック添加によって炭化
珪素の結晶成長を抑止しながら効果的な焼結を行ない得
るものであり、カーボンブラックが所定の範囲を外れて
少ない場合にはそれだけ結晶成長の危険が大きくなり、
又、所定の範囲を外れて多い場合は無駄な添加量の増大
により焼結能率を低下させるとともに、品質低下を来す
こともあり得るものである。In the present invention, if a powder of 1 μm or less is used as α-silicon carbide, a dense sintered body can be obtained most effectively, and in particular, the crystal growth of silicon carbide can be suppressed by adding 1 to 5% by volume of carbon black. However, if the amount of carbon black is outside the specified range, the risk of crystal growth increases accordingly.
Furthermore, if the amount exceeds the predetermined range, the sintering efficiency will decrease due to an unnecessary increase in the amount added, and the quality may also deteriorate.
次に実施例について説明する。Next, an example will be described.
実施例1
平均粒径0.8μmのα・SiC粉末と、これに対し0
.5重量%の炭化硼素と8.0重量%のフェノール樹脂
とを添加したものに、カーボンブラックを5体積%添加
し、水中で湿式混合した後、乾燥し、篩通しを経てから
、30mm X 10mm X 5 mmの寸法に成形
した。Example 1 α・SiC powder with an average particle size of 0.8 μm and
.. 5% by volume of carbon black was added to a mixture of 5% by weight of boron carbide and 8.0% by weight of phenolic resin, wet mixed in water, dried, and passed through a sieve to form a 30mm x 10mm product. It was molded to a size of 5 mm.
次に窒素中に於て800℃で60分間仮焼し、ついで2
100°Cのアルゴン雰囲気中で60分間常圧焼結した
。Next, it was calcined in nitrogen at 800℃ for 60 minutes, and then
Normal pressure sintering was performed in an argon atmosphere at 100°C for 60 minutes.
仮焼体及び焼結体をそれぞれめのう乳鉢で粉砕して粉末
となし、X線回折装置により回折を行ったところ、第1
図(イ)及び(ロ)に示すように添加したカーボンブラ
ックはすべて黒鉛化して焼結体中に存在していることが
判った。The calcined body and the sintered body were each crushed into powder in an agate mortar and diffracted using an X-ray diffraction device.
As shown in Figures (a) and (b), it was found that all of the added carbon black was graphitized and present in the sintered body.
実施例2
実施例1と同様にして得られた焼結体を平面研削した後
、9μmのダイヤモンドで湿式研磨し、光学顕微鏡によ
って焼結体中に存在する黒鉛の分散状態を観察した。ま
た、その後研磨面を村上試薬によってエツチングし、S
iC粒径やSiCの粒界に存在する黒鉛の粒径を観察し
た。Example 2 A sintered body obtained in the same manner as in Example 1 was surface-ground and then wet-polished with a 9 μm diamond, and the state of dispersion of graphite present in the sintered body was observed using an optical microscope. After that, the polished surface was etched with Murakami's reagent, and S
The iC grain size and the graphite grain size existing at the grain boundaries of SiC were observed.
比較のためカーボンブラックの添加をしないで同様に処
理した焼結体とカーボンブラックの代りに黒鉛粉末を添
加した焼結体をつくり、試験を行なった結果は、第2図
の顕微鏡写真(11の無添加焼結体、同(2)の黒鉛添
加焼結体及び(3)に示したこの発明に従うカーボンブ
ラック添加焼結体を対比して明らかな通り、無添加の場
合はSiCの粒成長が激しく、黒鉛添加により結晶成長
は若干抑制されるが、カーボンブラック添加によって黒
鉛添加の場合よりも尚一層微細でち密な焼結体が得られ
ている。For comparison, a sintered body treated in the same manner without the addition of carbon black and a sintered body with graphite powder added instead of carbon black were made and tested. The results are shown in the micrograph in Figure 2 (No. 11). As is clear from the comparison of the additive-free sintered body, the graphite-added sintered body of (2), and the carbon black-added sintered body according to the present invention shown in (3), in the case of no additive, the grain growth of SiC is Although the crystal growth is severely suppressed to some extent by the addition of graphite, the addition of carbon black yields a finer and denser sintered body than in the case of the addition of graphite.
実施例3
実施例1におけるカーボンブラックの添加量を表1のよ
うに変化させて焼結した焼結体の嵩密度を測定した後、
4n+mX 8mmX25mmの寸法に平面研削して3
点曲げ強度を測定した。その結果を表1に示す。この結
果からカーボンブラックの添加量が1体積%以上5体積
%までになると、未添加品に比べて抗折強度が20%程
度上昇していることが判る。Example 3 After measuring the bulk density of the sintered body obtained by changing the amount of carbon black added in Example 1 as shown in Table 1,
Surface grind to dimensions of 4n+mX 8mmX25mm 3
Point bending strength was measured. The results are shown in Table 1. From these results, it can be seen that when the amount of carbon black added is 1% to 5% by volume, the bending strength increases by about 20% compared to the product without the addition of carbon black.
表1
実施例4
実施例3と同様にして得られた焼結体を4鶴×3mmX
25mmの寸法に平面研削してそれぞれの熱衝撃温度(
ΔT)を測定した。測定方法としては水中急冷法を用い
、種々な温度(T”C)で15分間保持した後に、水中
(TO”C)に投下し、その後に試料の抗折強度の劣化
が見られない限界温度ΔT=T−Toを測定した。Table 1 Example 4 A sintered body obtained in the same manner as Example 3 was
The surface was ground to a size of 25 mm and the thermal shock temperature (
ΔT) was measured. The measurement method uses an underwater quenching method, and after holding the sample at various temperatures (T"C) for 15 minutes, it is dropped into water (TO"C), and then the limit temperature at which no deterioration of the bending strength of the sample is observed is determined. ΔT=T−To was measured.
その結果を表2に示す。The results are shown in Table 2.
この結果カーボンブラックの添加量を増やすに従い熱衝
撃抵抗は上昇し、5体積%添加で熱衝撃温度(ΔT)は
ほぼ100℃も上昇することが判った。As a result, it was found that as the amount of carbon black added increases, the thermal shock resistance increases, and when 5% by volume is added, the thermal shock temperature (ΔT) increases by almost 100°C.
表 2
実施例5
実施例3と同様にして外径30鰭内径20鰭厚さ5龍の
リングを焼結し、摺動面を平面研削した後9μmのダイ
ヤモンドで湿式研磨仕上げし、下記の条件で湿式摺動試
験を行なった。その結果を表3に示す。Table 2 Example 5 A ring with an outer diameter of 30, an inner diameter of 20, and a fin thickness of 5 was sintered in the same manner as in Example 3, and the sliding surface was surface-ground and then wet-polished with a 9 μm diamond, under the following conditions. A wet sliding test was conducted. The results are shown in Table 3.
この結果からカーボンブラックを1体積%以上添加した
場合、このカーボンブラックが黒鉛となリSiC粒界に
存在する焼結体の動摩擦係数は無添加品に比べて20%
以上小さくなっており、又摩耗量も半減していることが
判る。These results show that when 1% or more of carbon black is added, this carbon black converts into graphite, and the coefficient of dynamic friction of the sintered body existing at the SiC grain boundaries is 20% higher than that of a product without additives.
It can be seen that the amount of wear has been reduced by half, and the amount of wear has been reduced by half.
然し、30体積%もの大量添加をしたものは、理論密度
の80%にも焼結しておらず、動摩擦係数や摩耗量が大
きくなることが判った。However, it was found that when a large amount of 30% by volume was added, the sintering did not reach even 80% of the theoretical density, and the coefficient of dynamic friction and amount of wear increased.
なお摺動条件は次の通りである。The sliding conditions are as follows.
試験機 メカニカルシールタイプ(リングオンリング方
式)
%式%
本発明は上記の比較試験からも明らかな通り、摩擦係数
、抗折強度、熱衝撃温度等の緒特性に優れた炭化珪素・
黒鉛複合焼結体を比較的簡単な工程で製造することがで
きる。Testing machine Mechanical seal type (ring-on-ring method) % formula % As is clear from the above comparative tests, the present invention uses silicon carbide, which has excellent properties such as friction coefficient, bending strength, and thermal shock temperature.
A graphite composite sintered body can be manufactured through a relatively simple process.
第1図(イ)、(ロ)は、焼結前の仮焼体と焼結体とに
ついてのX′fa回折グラフ、第2図はカーボンブラッ
ク無添加焼結体、黒鉛添加焼結体及びカーボンブラック
添加焼結体についての顕微鏡写真である。
第1図
(イ)
(焼結前2
(ill)
2θ(de >)
手 続 補 正 書
昭和61年 7月16日
特許庁長官 黒 1) 明 雄 殿1、事件の
表示
昭和61年特許願第96399号
2、発明の名称
炭化珪素・黒鉛複合焼結体
3、補正をする者
事件との関係 特許出願人
(454)日本特殊陶業株式会社
4、復代理人
住 所 ■100東京都千代田区霞が関二丁目2番4号
霞山ビルディング7階 電話(581)2241番(代
表)(訂正)明 細 書
1、発明の名称 炭化珪素・黒鉛複合焼結体2、特許
請求の範囲
1、 α炭化珪素の常圧焼結体であって、SiC粒界に
第2相として、カーボンブラックを′とじて ロに里
ヒした、平均粒径3μm以下の黒鉛が、炭化珪素量に
対し7て1〜5体積%の割合で均一に分散して存在し、
Σ匹−Ω理論密度の90%以上の密度を有することを特
徴とする炭化珪素・黒鉛複合焼結体。
3、発明の詳細な説明
(産業上の利用分野)
本発明は高密度高強度の、炭化珪素・黒鉛複合焼結体に
関するものである。
炭化珪素は極めて優れた化学的・物理的性質を有してい
るため、摺動材料、高温構造材料ないしは耐食性材料と
して注目されている。
例えばメカニカルシールリングや、プランジャー、軸受
、その他サンドブラストノズル、タペット又は電波吸収
体などとして数多、利用が可能で(従来の技術)
炭化珪素焼結体は、その一般的な製造方法として、反応
焼結法、ホットプレス法さらには無加圧、すなわち常圧
焼結法などによるものが知られ、その中で常圧焼結法の
採用は最も有利であるが、炭化珪素は元来、難焼結性の
材料であるため無加圧下で充分に焼結させることは従来
困難であるとされて来た。
しかし、最近各種の焼結助剤が開発され、前記の困難性
を克服する試みがなされている。その代表的なものにつ
いて、炭化珪素の結晶形削に見ると次の通りである。
即ち特開昭51−148712号公報によればα炭化珪
素に、0.15〜3.0重量%の硼素と、0.5〜5.
0重量%の炭素に相当する炭素質有機材料、さらに1.
0重量%までの付加的な炭素を混合成形し、次にこの成
形体を少なくとも2.4g7cm3即ち理論密度の75
%以上に焼結する方法が開示されている。
一方特開昭50−78609号公報によればβ炭化珪素
含有化合物と、0.1〜1.0重量%の炭素に相当する
量の炭素質添加剤とを混合成形して少なくとも理論密度
の85%を有する炭化珪素焼結体を得る方法が開示され
、ここで用いられている炭素質添加剤については、炭化
珪素粉末中に常に少量において存在しているか又は加熱
に際して粉末表面に吸着された酸素から形づくられるか
のようなシリカの還元や遊離珪素のゲッター(捕捉体)
として働くこと、しかし1.0重量%以上添加した場合
にはその未反応過剰炭素は永久的な細孔と酷似した作用
のもとに最終的に到達し得る密度と強度とを制限するこ
と、などが述べられている。
(発明が解決しようとする問題点)
このような従来方法によれば、炭化珪素の結晶形に拘わ
らず、ち密な焼結体を得るため2000℃以上の高温下
に於て焼結を行なうとき、β炭化珪素はα炭化珪素への
変態に伴ない粒成長を起し、またα炭化珪素に於ては相
変態こそ起さないものの、やはり粒成長を起すことが、
微細でち密な焼結体を得る妨げとなることが解決をすべ
き問題点として指摘される。
(問題点を解決するための手段)
このような状況に鑑み種々研究の結果、発明者らはとく
にα炭化珪素の焼結において炭素がSiCの粒成長抑制
作用を持つことに着目し、上述したところにおいて3重
量%以下の硼素、又は硼素化合物(この場合硼素に換算
して好ましくは0.1〜3重量%とくに好ましくは0.
1〜1.0重量%)を用いるを例とする焼結助剤とは別
に、カーボンブラックをα炭化珪素に対し1〜5体積%
添加すれば、それが焼結時にはSiC粒の成長を抑制す
るだけでなく、焼結後には第2相成分として微細で均一
な状態にてSiC粒界に、予想外にも黒鉛として存在す
ることになり、耐熱衝撃性に優れた微細でち密な炭化珪
素・黒鉛複合焼結体を得ることに成功したものである。
ここにカーボンブラックの如き無定形炭素の黒鉛化には
通常2500〜3000℃の高温加熱を要するにも拘わ
らず、α炭化珪素焼結過程で上記黒鉛化を起すことが発
見されたのである。
すなわちこの発明はα炭化珪素の常圧焼結体であって、
SiC粒界に第2相として、カーボンブラックを出発物
質として焼結時に黒鉛化した、平均粒径3μm以下の黒
鉛が、炭化珪素量に対して1〜5体積%の割合で均一に
分散して存在し、SiCの理論密度の90%以上の密度
を有することを特徴とする炭化珪素・黒鉛複合焼結体で
ある。
かくして得られる炭化珪素・黒鉛焼結体は、従来方法に
従い粒成長が余儀なくされた炭化珪素焼結体と比べて、
機械的曲げ強度が20%以上上昇し、また熱衝撃温度が
従来のものに比べて90〜200℃も上昇することかた
しかめられた。
カーボンブラックの添加がα炭化珪素の焼結中に黒鉛化
をもたらして、炭化珪素・黒鉛複合焼結体中のSiC粒
界に黒鉛として存在することによって、従来の炭化珪素
焼結体に比べて動摩擦係数を20%以上も低下させ、し
かも第2相としてSiC粒界に存在する黒鉛は耐食性に
優れているので、炭化珪素の有する化学的安定性を何ら
劣化させることはない。
(作 用)
この発明において、カーボンブラックの重要性は次の通
りである。
すなわちフェノール樹脂のような炭素質有機化合物を、
かりにカーボンブラック添加の代替にもなるように増量
した場合には、均一に分散混合することはできてもフェ
ノール樹脂自体にバインダーとしての性質があるので、
たとえばα炭化珪素に対し10重量%以上のように添加
した場合には、任意の形状への成形などの生加工をする
ことが困難になり、かつ添加したフェノール樹脂の約5
0%は低温に於て飛散するため、仮焼時に生密度が極端
に低下して、焼結性を妨げる。
またカーボンブラックの代りにはじめから黒鉛粉末を配
合した場合には、カーボンブラック添加に比べて焼結中
におけるα炭化珪素粒子の粒成長抑制作用を事実上止じ
ないし、抗折強度の上昇も見られなかった。
カーボンブラックは、α炭化珪素に対し1体積%よりも
少ないときは添加効果が不充分な一方、5体積%を土建
るときは炭化珪素の焼結性を低下させてそのすぐれた緒
特性を損う。
本発明でα炭化珪素として1μm以下の粉末を用いて、
最も効果的にち密な焼結体を得ることができ、とくに1
〜5体積%のカーボンブラック添加によって炭化珪素の
結晶成長を抑止しながら効果的な焼結を行ない得るもの
であり、カーボンブラックが所定の範囲を外れて少ない
場合にはそれだけ結晶成長の危険が太き(なり、又、所
定の範囲を外れて多い場合は無駄な添加量の増大により
焼結能率を低下させるとともに、品質低下を来すことも
あり得るものである。
SiC粒界中に第2相として存在する黒鉛の平均粒径は
、3μm以下でなければならない。それというのは3μ
mをこえて大きい粒径の黒鉛は、α炭化珪素の焼結性や
強度を却って低下させるからである。
(実施例)
実施例1
平均粒径0.8μmのα炭化珪素粉末と、これに対し0
.5重量%の炭化硼素と8.0重量%のフェノール樹脂
とを添加し、これに加えてカーボンブラックを5体積%
添加し、水中で湿式混合した後、乾燥し、篩通しを経て
から、30mm X 10mm x 5 mmの寸法に
成形した。
次に窒素中に於て800℃で60分間仮焼し、ついで2
100°Cのアルゴン雰囲気中で60分間常圧焼結した
。
仮焼体及び焼結体をそれぞれめのう乳鉢で粉砕して粉末
となし、X線回折装置により回折を行ったところ、第1
図(イ)及び(ロ)に示すように添加したカーボンブラ
ックはすべて黒鉛化して焼結体中に存在していることが
判った。
実施例2
実施例1と同様にして得られた焼結体を平面研削した後
、9μmのダイヤモンドで湿式研磨し、光学顕微鏡によ
って焼結体中に存在する黒鉛の分散状態を観察した。ま
た、その後研磨面を村上試薬によってエツチングし、S
iC粒内やSiC粒界に存在する黒鉛の粒径を観察した
。
比較のためカーボンブラックの添加をしないで同様に処
理した焼結体と、カーボンブラックの代りに黒鉛粉末を
添加した焼結体とをつくり、試験を行なった結果は、第
2図の顕微鏡写真+11の無添加焼結体、同(2)の黒
鉛添加焼結体及び(3)に示したこの発明に従うカーボ
ンブラック添加焼結体を対比して明らかな通り、無添加
の場合はSiCの粒成長が激しく、黒鉛添加により結晶
成長は若干抑制されるが、カーボンブラック添加によっ
て黒鉛添加の場合よりも尚一層微細でち密な焼結体が得
られている。
実施例3
実施例1におけるカーボンブラックの添加量を表1のよ
うに変化させて焼結した焼結体の嵩密度を測定した後、
4 mmX 8 mmX25mmの寸法に平面研削して
3点曲げ強度を測定した。その結果を表1に示す。この
結果からカーボンブラックの添加量が1体積%以上5体
積%までにて、無添加品に比べて抗折強度が2.30%
をこえる程度にも著しく上昇し、黒鉛添加はむしろ低減
傾向を呈しているのと対照的である。
表1
実施例4
実施例3と同様にして得られた焼結体を、やはり4龍X
3mmX25++nの寸法に平面研削してそれぞれの熱
衝撃温度(ΔT)を測定した。測定方法としては水中急
冷法を用い、種々な温度(T”C)で15分間保持した
後に、水中(T、℃)に投下し、その後に試料の抗折強
度の劣化が見られない限界温度ΔT=T−T、を測定し
た。
その結果を表2に示す。
この結果からカーボンブラックの添加による熱衝撃抵抗
の上昇は、1〜5体積%添加で熱衝撃温度(ΔT)がほ
ぼ100℃にも達することが判った。
表2
実施例5
実施例3と同様にして外径30B内径20龍厚さ5鶴の
リングを焼結し、摺動面を平面研削した後9μmのダイ
ヤモンドで湿式研磨仕上げし、下記の条件で湿式摺動試
験を行なった。その結果を表3に示す。
この結果からカーボンブラックを1体積%以上添加した
場合、このカーボンブラックが黒鉛となりSiC粒界に
存在する焼結体の動摩擦係数は無添加品に比べて20%
以上小さくなっており、又摩耗量も半減していることが
判る。
然し、5体積%をこえてとくに、30体積%もの大量添
加をしたものは、理論密度の80%にも焼結しておらず
、動摩擦係数や摩耗量が却って大きくなることが判った
。
なお摺動条件は次の通りである。
試験機 メカニカルシールタイプ(リングオンリング方
式)
%式%
実施例1において、カーボンブラック、黒鉛とも粒径を
異ならせて添加し、実施例1と同様にして焼結した焼結
体を、実施例2と同様にしてエツチングした後、走査型
電子顕微鏡(SEM)でSiC粒界に存在する黒鉛の平
均粒径を測定した。次に実施例3と同様にして焼結体の
密度と抗折強度を測定し、SiC粒界に存在する黒鉛の
粒径との関係を調査し、その結果を表4に示す。
この結果から約3μmよりも大きい粒径の黒鉛が存在す
るとα炭化珪素の常圧下の焼結性や強度を却って低下さ
せること、また試料番号18 、19の比較からカーボ
ンブラックの使用が、黒鉛(2,5μmは下限粒径)の
場合に比し、粒成長抑制作用がより著しいことにあわせ
知れる。
表4
□□□=
以上の各実施例では簡単のためカーボンブラックと黒鉛
との各添加量にて供試片を区別したが、実際に焼結体中
のSiC粒界に存在する黒鉛量については、焼結体を粉
砕して粉末状態にした後、850°Cの酸素気流中で燃
焼させて黒鉛が燃焼して発生するCO又はCO□ガス量
を検出することにより定量することが出来る。以下その
具体例を示す。
実施例7
実施例3において得られた焼結体を、それぞれめのう乳
鉢で粉砕して粉末状態にした後、それぞれのサンプルを
850℃×5分間酸素気流中で燃焼させて黒鉛が燃焼し
て発生ずるCO2ガス量をN a Ot+温溶液吸収さ
せて測定し、焼結体中に存在した黒鉛量を定量した。
この測定に際してはカーボンブラックを添加しない焼結
体を粉砕して粉末状態にした後ブランク試験を行い、各
測定結果の補正を行った。その結果を表5に示す。この
結果から添加したカーボンブラックの添加量にほぼ等し
い量の黒鉛が焼結体中に存在していることが判った。
表5
注:残存黒鉛量が添加量を上まわっている事例は、ブラ
ンク、供試品ともに、フェノール樹脂添加によって生じ
た誤差と考えられる。
(発明の効果)
本発明は上記の比較試験からも明らかな通り、摩擦係数
、抗折強度、熱衝撃温度等の緒特性に優れる点でを用な
炭化珪素・黒鉛複合焼結体である。
4、図面の簡単な説明
第1図(イ)、(ロ)は、焼結前の仮焼体と焼結体とに
ついてのX線回折グラフ、
第2図はカーボンブラック無添加焼結体、黒鉛添加焼結
体及びカーボンブラック添加焼結体についての顕微鏡写
真である。
特許出願人 日本特殊陶業株式会社
復代理人弁理士 杉 村 暁 秀手 続
補 正 書(方式)
%式%
1、事件の表示
昭和61年特許願第96399号
2、発明の名称
炭化珪素・黒鉛複合焼結体
3、補正をする者
事件との関係 特許出願人
名称(454)日本特殊陶業株式会社
4、復代理人
閾
5、補正命令の日付 昭和61年 7月29日1、
明細書第12頁の「4図面の簡単な説明」の欄を次のと
おりに訂正する。
「719図面の簡単な説明
第1図(イ)、(ロ)は、焼結前の仮焼体と焼結体とに
ついてのX線回折グラフ、Figures 1 (a) and (b) are X'fa diffraction graphs for the calcined body and sintered body before sintering, and Figure 2 is for the sintered body without carbon black, the sintered body with graphite added, and It is a micrograph of a carbon black added sintered compact. Figure 1 (a) (Before sintering 2 (ill) 2θ (de >) Procedure Amendment Book July 16, 1986 Commissioner of the Patent Office Black 1) Akio Tono 1, Indication of Case 1986 Patent Application No. 96399 2, Name of the invention Silicon carbide/graphite composite sintered body 3, Relationship to the case of the person making the amendment Patent applicant (454) Nippon Spark Plug Co., Ltd. 4, Sub-agent address ■100 Chiyoda-ku, Tokyo Kasumigaseki 2-2-4 Kasumiyama Building 7th floor Telephone number (581) 2241 (representative) (revised) Specification 1, Title of invention Silicon carbide/graphite composite sintered body 2, Claim 1, Alpha carbonization It is a pressureless sintered body of silicon, in which graphite with an average particle size of 3 μm or less is formed as a second phase at SiC grain boundaries by binding carbon black to 1 to 7 times the amount of silicon carbide. Uniformly dispersed in a proportion of 5% by volume,
A silicon carbide/graphite composite sintered body characterized by having a density of 90% or more of the theoretical density of Σ-Ω. 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a high-density, high-strength silicon carbide/graphite composite sintered body. Silicon carbide has extremely excellent chemical and physical properties, so it is attracting attention as a sliding material, a high-temperature structural material, or a corrosion-resistant material. For example, it can be used in many ways, such as mechanical seal rings, plungers, bearings, sandblasting nozzles, tappets, or radio wave absorbers (prior technology). Sintering methods, hot pressing methods, and non-pressure (pressureless) sintering methods are known. Among them, the pressureless sintering method is the most advantageous, but silicon carbide is inherently difficult to use. Since it is a sinterable material, it has conventionally been considered difficult to sinter it sufficiently without applying pressure. However, recently various sintering aids have been developed and attempts have been made to overcome the above-mentioned difficulties. Typical examples of this are as follows when looking at crystal shaping of silicon carbide. That is, according to JP-A-51-148712, 0.15 to 3.0% by weight of boron and 0.5 to 5% by weight of boron are added to α silicon carbide.
a carbonaceous organic material corresponding to 0% by weight of carbon; and 1.
Additional carbon up to 0 wt.
% or more is disclosed. On the other hand, according to JP-A No. 50-78609, a β silicon carbide-containing compound and a carbonaceous additive in an amount corresponding to 0.1 to 1.0% by weight of carbon are mixed and molded to form a compound with a theoretical density of at least 85% by weight. A method for obtaining a silicon carbide sintered body having a Reduction of silica and getter of free silicon as if formed from
However, when added in excess of 1.0% by weight, the unreacted excess carbon acts much like permanent pores, limiting the density and strength that can ultimately be achieved; etc. are stated. (Problems to be Solved by the Invention) According to such conventional methods, regardless of the crystal form of silicon carbide, when sintering is performed at a high temperature of 2000°C or higher to obtain a dense sintered body, , β-silicon carbide causes grain growth as it transforms into α-silicon carbide, and although α-silicon carbide does not undergo phase transformation, grain growth still occurs.
It is pointed out as a problem that must be solved that it is an obstacle to obtaining a fine and dense sintered body. (Means for solving the problem) In view of this situation, as a result of various studies, the inventors focused on the fact that carbon has the effect of suppressing the grain growth of SiC especially in the sintering of α-silicon carbide, and developed the above-mentioned method. By the way, 3% by weight or less of boron or a boron compound (in this case, preferably 0.1 to 3% by weight in terms of boron, particularly preferably 0.1 to 3% by weight).
Apart from the sintering aid (for example, 1 to 1.0% by weight), carbon black is used in an amount of 1 to 5% by volume relative to alpha silicon carbide.
If added, it not only suppresses the growth of SiC grains during sintering, but also unexpectedly exists as graphite at SiC grain boundaries in a fine and uniform state as a second phase component after sintering. We succeeded in obtaining a fine and dense silicon carbide/graphite composite sintered body with excellent thermal shock resistance. It has been discovered that although graphitization of amorphous carbon such as carbon black usually requires high temperature heating of 2500 to 3000°C, the above-mentioned graphitization occurs during the sintering process of α-silicon carbide. That is, the present invention is an atmospheric pressure sintered body of α silicon carbide,
As a second phase at SiC grain boundaries, graphite with an average particle size of 3 μm or less, which is graphitized during sintering using carbon black as a starting material, is uniformly dispersed at a ratio of 1 to 5% by volume based on the amount of silicon carbide. It is a silicon carbide/graphite composite sintered body characterized by having a density of 90% or more of the theoretical density of SiC. The silicon carbide/graphite sintered body obtained in this manner has a higher
It was confirmed that the mechanical bending strength increased by more than 20%, and the thermal shock temperature increased by 90 to 200°C compared to the conventional one. The addition of carbon black causes graphitization during sintering of α-silicon carbide, and by existing as graphite at the SiC grain boundaries in the silicon carbide/graphite composite sintered body, compared to conventional silicon carbide sintered bodies, Graphite, which lowers the coefficient of dynamic friction by 20% or more and is present in the SiC grain boundaries as a second phase, has excellent corrosion resistance, so it does not deteriorate the chemical stability of silicon carbide in any way. (Function) In this invention, the importance of carbon black is as follows. In other words, carbonaceous organic compounds such as phenolic resin,
However, if the amount is increased so that it can be used as a substitute for adding carbon black, even if it is possible to disperse and mix it uniformly, the phenol resin itself has properties as a binder.
For example, if it is added in an amount of 10% by weight or more based on α-silicon carbide, it becomes difficult to perform raw processing such as molding into an arbitrary shape, and approximately 5% of the added phenolic resin
Since 0% scatters at low temperatures, the green density is extremely reduced during calcination, impeding sinterability. Furthermore, when graphite powder is blended from the beginning instead of carbon black, compared to the addition of carbon black, the effect of suppressing the grain growth of α silicon carbide particles during sintering is not effectively stopped, and an increase in flexural strength is also observed. I couldn't. When carbon black is added at less than 1% by volume relative to α-silicon carbide, the effect of adding it is insufficient, while when it is added to α-silicon carbide at 5% by volume, it reduces the sinterability of silicon carbide and impairs its excellent properties. cormorant. In the present invention, using powder of 1 μm or less as α-silicon carbide,
A dense sintered body can be obtained most effectively, especially 1
By adding up to 5% by volume of carbon black, effective sintering can be performed while suppressing the crystal growth of silicon carbide, and if the amount of carbon black is outside the specified range and the amount is small, the risk of crystal growth increases accordingly. In addition, if the amount exceeds the specified range, the sintering efficiency will decrease due to an unnecessary increase in the amount added, and it may also lead to quality deterioration. The average particle size of the graphite present as a phase must be less than 3 μm.
This is because graphite having a particle size larger than m actually deteriorates the sinterability and strength of α-silicon carbide. (Example) Example 1 α silicon carbide powder with an average particle size of 0.8 μm and
.. 5% by weight of boron carbide and 8.0% by weight of phenolic resin, in addition to this, 5% by volume of carbon black.
After adding and wet-mixing in water, it was dried, passed through a sieve, and then molded into a size of 30 mm x 10 mm x 5 mm. Next, it was calcined in nitrogen at 800℃ for 60 minutes, and then
Normal pressure sintering was performed in an argon atmosphere at 100°C for 60 minutes. The calcined body and the sintered body were each crushed into powder in an agate mortar and diffracted using an X-ray diffraction device.
As shown in Figures (a) and (b), it was found that all of the added carbon black was graphitized and present in the sintered body. Example 2 A sintered body obtained in the same manner as in Example 1 was surface-ground and then wet-polished with a 9 μm diamond, and the state of dispersion of graphite present in the sintered body was observed using an optical microscope. After that, the polished surface was etched with Murakami's reagent, and S
The particle size of graphite present within iC grains and at SiC grain boundaries was observed. For comparison, a sintered body treated in the same manner without the addition of carbon black and a sintered body with graphite powder added instead of carbon black were made and tested.The results are shown in the micrograph in Figure 2 +11. As is clear from the comparison of the additive-free sintered body in (2), the graphite-added sintered body in (2), and the carbon black-added sintered body according to the present invention shown in (3), in the case of no additive, SiC grain growth Although the crystal growth is slightly suppressed by the addition of graphite, the addition of carbon black yields a finer and denser sintered body than in the case of addition of graphite. Example 3 After measuring the bulk density of the sintered body obtained by changing the amount of carbon black added in Example 1 as shown in Table 1,
Surface grinding was performed to a size of 4 mm x 8 mm x 25 mm, and the three-point bending strength was measured. The results are shown in Table 1. From this result, when the amount of carbon black added is 1% to 5% by volume, the bending strength is 2.30% higher than that of a product without additives.
This is in contrast to graphite addition, which shows a tendency to decrease. Table 1 Example 4 A sintered body obtained in the same manner as in Example 3 was also treated with 4Ryu
The surface was ground to a size of 3 mm x 25++n, and the thermal shock temperature (ΔT) of each was measured. The measurement method uses an underwater quenching method, and after holding the sample at various temperatures (T"C) for 15 minutes, it is dropped into water (T, °C), and then the limit temperature at which no deterioration of the bending strength of the sample is observed is determined. ΔT=T−T was measured. The results are shown in Table 2. From this result, the increase in thermal shock resistance due to the addition of carbon black was found to be such that the thermal shock temperature (ΔT) was approximately 100°C when 1 to 5% by volume was added. Table 2 Example 5 A ring with an outer diameter of 30 mm and an inner diameter of 20 mm and a thickness of 5 mm was sintered in the same manner as in Example 3, the sliding surface was surface ground, and then wet-grinded with a 9 μm diamond. After polishing, a wet sliding test was conducted under the following conditions.The results are shown in Table 3.The results show that when 1% by volume or more of carbon black is added, this carbon black becomes graphite and exists at the SiC grain boundaries. The coefficient of dynamic friction of the sintered body is 20% compared to additive-free products.
It can be seen that the amount of wear has been reduced by half, and the amount of wear has been reduced by half. However, it was found that when a large amount of addition of more than 5% by volume, especially as much as 30% by volume, was not sintered to even 80% of the theoretical density, the coefficient of dynamic friction and amount of wear increased on the contrary. The sliding conditions are as follows. Test machine Mechanical seal type (ring-on-ring method) % formula % In Example 1, carbon black and graphite were added with different particle sizes, and the sintered bodies were sintered in the same manner as in Example 1. After etching in the same manner as in 2, the average grain size of graphite present at SiC grain boundaries was measured using a scanning electron microscope (SEM). Next, the density and bending strength of the sintered body were measured in the same manner as in Example 3, and the relationship with the grain size of graphite present at the SiC grain boundaries was investigated. The results are shown in Table 4. This result shows that the presence of graphite with a particle size larger than about 3 μm actually reduces the sinterability and strength of α-silicon carbide under normal pressure, and from a comparison of sample numbers 18 and 19, the use of carbon black shows that graphite ( It is also known that the grain growth inhibiting effect is more remarkable than in the case where the grain size is 2.5 μm (the lower limit grain size). Table 4 □□□= In each of the above examples, the test pieces were distinguished by the amounts of carbon black and graphite added for simplicity, but the actual amount of graphite present at the SiC grain boundaries in the sintered body can be quantified by crushing the sintered body into a powder state, then burning it in an oxygen stream at 850°C and detecting the amount of CO or CO□ gas generated by combustion of graphite. A specific example will be shown below. Example 7 Each of the sintered bodies obtained in Example 3 was ground into powder in an agate mortar, and then each sample was burned at 850°C for 5 minutes in an oxygen stream to cause the graphite to burn and emit light. The amount of CO2 gas produced was measured by absorbing NaOt+ warm solution, and the amount of graphite present in the sintered body was quantified. For this measurement, a sintered body to which no carbon black was added was ground into a powder state, a blank test was conducted, and each measurement result was corrected. The results are shown in Table 5. From this result, it was found that an amount of graphite approximately equal to the amount of added carbon black was present in the sintered body. Table 5 Note: Cases in which the amount of residual graphite exceeds the amount added are considered to be errors caused by the addition of phenolic resin in both blanks and test samples. (Effects of the Invention) As is clear from the above comparative tests, the present invention is a silicon carbide/graphite composite sintered body that is excellent in properties such as friction coefficient, flexural strength, and thermal shock temperature. 4. Brief explanation of the drawings Figures 1 (a) and (b) are X-ray diffraction graphs of the calcined body and sintered body before sintering, Figure 2 is the sintered body without carbon black added, 1 is a micrograph of a graphite-added sintered body and a carbon black-added sintered body. Patent applicant: NGK SPARK PLUG Co., Ltd. Patent attorney: Hide Sugimura
Amendment (method) % formula % 1. Indication of the case Patent Application No. 96399 of 1985 2. Name of the invention Silicon carbide/graphite composite sintered body 3. Person making the amendment Relationship to the case Name of the patent applicant ( 454) NGK Spark Plug Co., Ltd. 4, sub-agent threshold 5, date of amendment order July 29, 1988 1,
The column "Brief explanation of 4 drawings" on page 12 of the specification is corrected as follows. 719 Brief explanation of drawings Figures 1 (a) and (b) are X-ray diffraction graphs of the calcined body and sintered body before sintering,
Claims (1)
として平均粒径3μm以下の黒鉛が、炭化珪素量に対し
て1〜5体積%の割合で均一に分散して存在し、理論密
度の90%以上の密度を有することを特徴とする炭化珪
素・黒鉛複合焼結体。 2、第2相の黒鉛が、カーボンブラックを出発物質とし
て、焼結時に黒鉛化したものである特許請求の範囲第1
項記載の炭化珪素・黒鉛複合焼結体。[Claims] 1. A sintered body of α-silicon carbide, in which graphite with an average grain size of 3 μm or less is contained as a second phase at SiC grain boundaries at a ratio of 1 to 5% by volume based on the amount of silicon carbide. A silicon carbide/graphite composite sintered body, which is uniformly dispersed and has a density of 90% or more of the theoretical density. 2. Claim 1, wherein the second phase graphite is graphitized during sintering using carbon black as a starting material.
The silicon carbide/graphite composite sintered body described in .
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP61096399A JPS6265973A (en) | 1986-04-25 | 1986-04-25 | Silicon carbide/graphite composite sintered body |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP61096399A JPS6265973A (en) | 1986-04-25 | 1986-04-25 | Silicon carbide/graphite composite sintered body |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS6265973A true JPS6265973A (en) | 1987-03-25 |
Family
ID=14163885
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP61096399A Pending JPS6265973A (en) | 1986-04-25 | 1986-04-25 | Silicon carbide/graphite composite sintered body |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6265973A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4998458B2 (en) * | 2006-02-24 | 2012-08-15 | 日立化成工業株式会社 | Ceramic sintered body, sliding component using the same, and method for producing ceramic sintered body |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3966855A (en) * | 1974-02-22 | 1976-06-29 | The United States Of America As Represented By The Secretary Of The Air Force | Method of fabricating silicon carbide articles |
-
1986
- 1986-04-25 JP JP61096399A patent/JPS6265973A/en active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3966855A (en) * | 1974-02-22 | 1976-06-29 | The United States Of America As Represented By The Secretary Of The Air Force | Method of fabricating silicon carbide articles |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4998458B2 (en) * | 2006-02-24 | 2012-08-15 | 日立化成工業株式会社 | Ceramic sintered body, sliding component using the same, and method for producing ceramic sintered body |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JPS6143310B2 (en) | ||
JPH0769731A (en) | High-strength, high-density conductive ceramic | |
JPH09175865A (en) | Production of alpha-type silicon carbide powder composition and its sintered compact | |
US4332755A (en) | Sintered silicon carbide - aluminum nitride articles and method of making such articles | |
CA1092615A (en) | High density hot pressed thermal shock resistant silicon carbide | |
EP0153000A1 (en) | Refractories of silicon carbide and related materials having a modified silicon nitride bonding phase | |
US5182059A (en) | Process for producing high density SiC sintered bodies | |
JPH1149572A (en) | Ceramic composite particles and their production | |
JPH02145484A (en) | Sintered silicon nitride | |
JPH01308876A (en) | Production of sic sintered compact having high density | |
KR101972350B1 (en) | A ZrC Composites and A Manufacturing method of the same | |
JPS6265973A (en) | Silicon carbide/graphite composite sintered body | |
JPS6360159A (en) | Manufacture of high density silicon carbide sintered body | |
KR102555662B1 (en) | Method for Preparing Silicon Nitride Sintered Body and The Silicon Nitride Sintered Body Prepared by The Same | |
JP2005119934A (en) | Silicon nitride porous body and method of manufacturing the same | |
JP2649220B2 (en) | Silicon nitride / silicon carbide composite powder, composite compact, method for producing them, and method for producing silicon nitride / silicon carbide composite sintered body | |
JP3616829B2 (en) | Carbon-boron carbide sintered body, method for producing the same, and material using the sintered body | |
JP2005298304A (en) | Highly dense silicon carbide ceramic and its producing method | |
JPH01242465A (en) | Production of silicon carbide sintered body and sliding member thereof | |
Schwetz et al. | Toughness and Hardness of Lps‐Sic and Lps‐Sic Based Composites | |
JPS6346029B2 (en) | ||
JPS60255672A (en) | Manufacture of silicon carbide sintered body | |
JP2826080B2 (en) | Silicon nitride / silicon carbide composite sintered body and method for producing composite powder | |
JP3567001B2 (en) | Method for producing composite sintered body of silicon carbide and silicon nitride | |
JPS63117962A (en) | Silicon carbide base sintered body and manufacture |