JPH02311363A - Production of ceramic sintered compact - Google Patents

Production of ceramic sintered compact

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Publication number
JPH02311363A
JPH02311363A JP1132298A JP13229889A JPH02311363A JP H02311363 A JPH02311363 A JP H02311363A JP 1132298 A JP1132298 A JP 1132298A JP 13229889 A JP13229889 A JP 13229889A JP H02311363 A JPH02311363 A JP H02311363A
Authority
JP
Japan
Prior art keywords
ceramic sintered
sintered body
sintered compact
sic
gas
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
Application number
JP1132298A
Other languages
Japanese (ja)
Inventor
Mikio Sakai
幹雄 酒井
Yoshio Akimune
淑雄 秋宗
Naoto Hirosaki
尚登 広崎
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nissan Motor Co Ltd
Original Assignee
Nissan Motor Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nissan Motor Co Ltd filed Critical Nissan Motor Co Ltd
Priority to JP1132298A priority Critical patent/JPH02311363A/en
Publication of JPH02311363A publication Critical patent/JPH02311363A/en
Pending legal-status Critical Current

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Abstract

PURPOSE:To obtain the subject high-density sintered compact with both high mechanical strength and breaking toughness, also usable for structural parts of complicated shape by coating the surface of a non-oxide-based Si ceramic sintered compact with a dense film of the same components as those for said sintered compact followed by pressurized heating using a pressurizing gas and sintering again. CONSTITUTION:The surface of a ceramic sintered compact consisting mainly of SiC or Si3N4 etc., is coated with a gas-impermeable dense film of ca.several mum thickness consisting mainly of the same components as the chief components for said sintered compact through e.g. a chemical vapor deposition process. Thence, using a pressurizing gas such as Ar or N2, an atmosphere >=5MPa in pressure is heated and pressurized to sinter the above product again to the density >=95% of its theoretical density, thus obtaining the objective ceramic sintered compact of both high mechanical strength and toughness.

Description

【発明の詳細な説明】[Detailed description of the invention] 【発明の目的】[Purpose of the invention]

(産業上の利用分野) 本発明は、自動車9機械装置、化学装置、宇宙航空機器
などの幅広い分野において使用される各種構造部品の素
材として利用され、特に高強度・高靭性を有しているこ
とが要求されると共に複雑な形状を有している構造部品
にも適用することができるセラミックス焼結体を製造す
るのに適したセラミックス焼結体の製造方法に関するも
のである。 (従来の技術) 従来、この種のセラミックス焼結体としては、炭化珪素
(S i C)に代表される炭化物系のものや、窒化珪
素(Si3N4)に代表される窒化物系のものなど、各
種のものがある。 これらのうち、例えば、SiC系のセラミックス焼結体
は、例えばSiC粉末にB粉末やC源を添加して得られ
る混合粉末を成形した後、Arガス1気圧中あるいは真
空中において焼結することにより、比較的容易にかつ良
好な量産性のもとでSiC系のセラミックス焼結体が得
られることが知られている。 しかしながら、このようなSiC系のセラミックス焼結
体はSiC単相で構成されているため、靭性がさほど良
くないという課題を有していた。 また、Si3N4系のセラミックス焼結体は、Si3N
4単独では焼結が困難であるため、通常の場合、窒化珪
素粉末に、MgO。 A n 203 、 Y 203などの焼結助剤を添加
してN2ガス中やAr+N2ガス中において焼結するこ
とにより、比較的容易にかつ良好な量産性のもとでSi
3N4系のセラミックス焼結体が得られることが知られ
ている。 しかしながら、このようなSi3N4系のセラミックス
焼結体においてもSi3N4を主体として構成されてい
るため、強度および靭性のより一層の向」二には不十分
であるという課題を有していた。 そこで、セラミックスの母相を単相とするのではなく、
ウィスカーや異質粒子を複合化させることによって、よ
り一層強靭なセラミックス焼結体を開発しようとする試
みも行なわれている。 このような複合セラミックス焼結体を製造する方法とし
ては、 (1)常圧焼結法 (2)ホットプレス法 (3)反応焼結法(例えば、SiとSiCウィスカーと
の混合成形体に、高温でN2ガスを流しながら、Siと
N2を反応させて焼結する方法) (4)熱間等方圧圧縮(HI P)法 などが広く採用されてきた。 なお、SiC系のセラミックス焼結体の製造方法は、例
えば、特開昭50−78609号、特開昭56−921
67号、特開昭61−168568号、特開昭63−2
06352号など数多くの技術文献に記載されたものが
あり、また、Si3N4系のセラミックス焼結体の製造
方法は、例えば、特開昭49−63710号、特開昭5
4−15916号、特開昭57−71872号、特開昭
58−60673号、特開昭60−137873号など
数多くの技術文献に記載されたものがある。 (発明が解決しようとする課題) しかしながら、このような従来の複合セラミックス焼結
体の製造方法にあっては、複合化に用いるウィスカーや
異質粒子が焼結の促進を大きく抑制するため、常圧焼結
法では理論密度比95%以上の緻密で高強度の焼結体を
得ることが困難であるという課題があった。 一方、焼結時に粉末を加圧するホットプレス法では、複
合セラミックス焼結体であっても緻密なものを比較的容
易に得ることが可能であるが、−軸方向の加圧焼結であ
るために複雑な形状の構造部品には適用できがたいとい
う課題があった。 さらに、反応焼結法では、緻密な焼結体を得ることが困
難であり、熱間等方圧圧縮法では、緻密で複雑な形状の
焼結体が得られるもののガラスカプセルの成形や焼結後
のカプセルの除去、さらには焼結体表面の仕上げ処理な
どといった生産性を著しく低下させる作業が必要であり
、実際の量産には不向きであるという課題があった。 (発明の目的) 本発明は、このような従来の課題にかんがみてなされた
もので、強度および破壊靭性などの機械的特性に優れて
いると共に、複雑形状部品の製造も容易に可能であり、
量産性が要求される場合にも適しているセラミックス焼
結体の製造方法を提供することを目的としている。
(Field of Industrial Application) The present invention can be used as a material for various structural parts used in a wide range of fields such as automobile machinery, chemical equipment, and aerospace equipment, and has particularly high strength and toughness. The present invention relates to a method for manufacturing a ceramic sintered body that is suitable for manufacturing a ceramic sintered body that is required to produce a ceramic sintered body and can be applied to structural parts having a complicated shape. (Prior Art) Conventionally, this type of ceramic sintered body has been made of carbide-based materials such as silicon carbide (S i C), nitride-based materials such as silicon nitride (Si3N4), etc. There are various types. Among these, for example, a SiC-based ceramic sintered body is produced by molding a mixed powder obtained by adding B powder or a C source to SiC powder, and then sintering it in 1 atmosphere of Ar gas or in a vacuum. It is known that a SiC-based ceramic sintered body can be obtained relatively easily and with good mass productivity. However, since such a SiC-based ceramic sintered body is composed of a single phase of SiC, it has a problem in that its toughness is not so good. In addition, Si3N4-based ceramic sintered bodies are Si3N4-based ceramic sintered bodies.
Since sintering is difficult with 4 alone, MgO is usually added to silicon nitride powder. By adding sintering aids such as A n 203 and Y 203 and sintering in N2 gas or Ar+N2 gas, Si can be produced relatively easily and with good mass productivity.
It is known that a 3N4 ceramic sintered body can be obtained. However, since such a Si3N4-based ceramic sintered body is mainly composed of Si3N4, it has the problem that it is insufficient for achieving further improvements in strength and toughness. Therefore, instead of making the matrix of ceramics a single phase,
Attempts are also being made to develop even stronger ceramic sintered bodies by compositing whiskers and foreign particles. Methods for manufacturing such a composite ceramic sintered body include: (1) normal pressure sintering method (2) hot pressing method (3) reaction sintering method (for example, by forming a mixed molded body of Si and SiC whiskers, (4) Hot isostatic pressing (HIP) method has been widely adopted. The method for manufacturing SiC ceramic sintered bodies is described in, for example, JP-A-50-78609 and JP-A-56-921.
No. 67, JP-A-61-168568, JP-A-63-2
There are many methods described in technical documents such as No. 06352, and methods for manufacturing Si3N4 ceramic sintered bodies are described in, for example, JP-A-49-63710 and JP-A-5.
There are those described in many technical documents such as JP-A No. 4-15916, JP-A-57-71872, JP-A-58-60673, and JP-A-60-137873. (Problem to be Solved by the Invention) However, in such conventional methods for manufacturing composite ceramic sintered bodies, whiskers and foreign particles used for composite greatly suppress the promotion of sintering, The problem with the sintering method is that it is difficult to obtain a dense, high-strength sintered body with a theoretical density ratio of 95% or more. On the other hand, with the hot press method, which presses the powder during sintering, it is possible to relatively easily obtain a dense composite ceramic sintered body, but because it is sintered under pressure in the -axial direction, However, there was a problem in that it was difficult to apply it to structural parts with complex shapes. Furthermore, with the reaction sintering method, it is difficult to obtain a dense sintered body, and with the hot isostatic pressing method, although a dense and complexly shaped sintered body can be obtained, it is difficult to form a glass capsule or sinter it. This method requires work such as subsequent removal of the capsule and finishing treatment of the surface of the sintered body, which significantly reduces productivity, making it unsuitable for actual mass production. (Objective of the Invention) The present invention has been made in view of such conventional problems, and it has excellent mechanical properties such as strength and fracture toughness, and can easily manufacture parts with complex shapes.
It is an object of the present invention to provide a method for manufacturing a ceramic sintered body that is suitable even when mass production is required.

【発明の構成】[Structure of the invention]

(課題を解決するための手段) 本発明に係る珪素の非酸化物系セラミックス焼結体の製
造方法は、珪素の非酸化物系セラミックス焼結体の表面
に該焼結体の主成分と同じ成分を主体とする緻密な被膜
を形成した後、加圧用ガスを用いて圧力5 M P a
以上の雰囲気にて加熱−加圧することにより理論密度比
95%以上に再焼結する構成としたことを特徴としてお
り、このようなセラミックス焼結体の製造方法の構成を
前述した従来の課題を解決するための手段としている。 本発明に係るセラミックス焼結体の製造方法においては
、SiCを主体とするセラミックス焼結体やSi3N4
を主体とするセラミックス焼結体が用いられるが、この
ような焼結体としては、SiC粉末やSi3N4粉末に
焼結助剤のほかにSiCウィスカーなどの強化繊維や炭
化物、窒化物などの強化粒子を混合して焼結したものが
用いられ、例えば通常の製造方法によって常圧焼結体(
理論密度比は80〜90%)としたものが用いられる。 そして、これらの強化繊維や強化粒子などの添加量は、
それらの種類などによって異なる場合もあるが、例えば
、SiCウィスカーの場合には20〜30体積%の範囲
で複合化したものが用いられる。 また、このSiCを主体とするセラミックス焼結体やS
i3N4を主体とするセラミックス焼結体の表面に、S
iCを主体とする緻密な被膜やSi3N4を主体とする
緻密な被膜を形成させるに際しては、蒸着法(例えば、
化学的蒸着法−CVD)などの適宜な手段を用いること
ができる。そして、この場合にいう緻密な被膜は、Si
C,Si3 N4.Ar、N2などのカスを通過させな
い程のガス不透過性の緻密な厚さ数pm程度のものとす
るのが好ましい。 次いで、前記SiCを主体とする緻密な被膜やSi3N
4を主体とする緻密な被膜を形成した後、加圧用ガスを
用いて圧力5 M P a以上の雰囲気にて加熱・加圧
することにより理論密度比95%以上に再焼結するが、
この場合には例えば加圧用ガスとしてArガスやN2ガ
スなどの不活性ガスを用いた熱間等方圧圧1fa(HI
 P)によって再焼結が行われる。 (発明の作用) 本発明に係るセラミックス焼結体の製造方法では、Si
Cを主体とするセラミックス焼結体の表面にSiCを主
体とするガス不透過性の緻密な被膜を形成した後、ある
いはSi3N4を主体とするセラミックス焼結体の表面
にSi3N4を主体とするガス不透過性の緻密な被膜を
形成した後、加圧用ガスを用いて圧力5 M P a以
上の雰囲気にて加熱・加圧することにより理論密度比9
5%以」二に再焼結する構成としているので、理論密度
比が80〜90%程度の焼結体の再焼結後には、理論電
度比が95%以上の高密度であって強度および破壊靭性
などの機械的特性に優れたセラミックス焼結体となる。 そして、複雑な形状が得られる常圧焼結法と同じく複雑
な形状が得られる熱間等方圧圧縮との組合わせにより高
富度でしかも複雑な形状部品が製造されるようになり、
再焼結する前の焼結体表面に形成したガス不透過性の緻
密な被膜が従来の熱間等方圧圧縮に用いるカプセル(容
器)に相当するものとなるので、従来のようなカプセル
の成形や焼結後のカプセルの除去さらには焼結体表面の
仕上げ処理などといった工程の省略がもたらされる。 (実施例) 実施例l SiC粉末(ベータランタム串ウルトラファイン:イビ
テン製)74gに、B粉末1gとフェノール樹脂5gを
加え、有機溶剤ジオキサンを用いて80時間ボールミル
を行った。 次いで、得られた混合物にSiCウィスカー(SCW#
1−105−0.7S:タテ水化学製)20gを添加し
、さらに20時間ボールミルを行った。 次に、ボールミルによって混合された混合物を液体N2
中に噴射することによって凍結した顆粒を得たのち、真
空乾燥法によりジオキサンを除去した。続いて、この乾
燥顆粒から圧粉成形体を成形し、フェノール樹脂を炭化
した後、真空中で2060℃X0.5hの焼結を行った
。このようにして得たSiCウィスカー/ S i C
複合セラミックス焼結体の密度は2.70g/Cm’ 
 (理論密度比84.1%〕であった。 次に、この複合セラミックス焼結体をメチルトリクロロ
シランCCH3Cl3S i)と過剰のN2ガスとの混
合ガス(CH30文3Si:H2=1:10)中1気圧
(0、98MP a)  。 1200℃において1時間静置させることによって、複
合セラミックス焼結体の表面にSiC被膜を形成させた
。なお、このときの被膜の形成は、次の化学反応に基づ
く気相化学反応(CVD)によるものである。 CH30M3 Si+excessH2+SiC+3H
C1+excessH2 この反応により形成されたSiC被膜の厚さは1〜2g
mであり、空孔や亀裂などといった欠陥は全く観察され
ない緻密なSiC被膜であった。 このようにして表面被覆を施したSiCウィスカー/ 
S i C複合セラミックス焼結体をArガス圧力15
MPa、温度2100°Cにおいて1時間保持して再焼
結を行った。 この再焼結によって得られた複合セラミックス焼結体の
密度は3.17g/cm3 (理論密度比98.8%)
であった。 また、抗折強度(3点…ロブ)および破壊靭性値(SE
PB法)はそれぞれ740MPaおよび6.8MPa−
51あった。 実施例2 Si3N4粉末(Hlグレード:シュタルク製)65g
に、Y2O3粉末LogとA文203粉末5gを加え、
エタノールを用いて80時間ボールミルを行った。 次いで、得られた混合物にSiCウィスカー(SCW#
1−105−0.7S:タテ水化学製)20gを添加し
、さらに20時間ボールミルを行った。 次に、ボールミルによって得られた混合物を噴霧加熱乾
燥して乾燥粉末を得たのち、この粉末を圧粉成形し、1
700°0.N2ガス1気圧中(0、98MP a)に
て1時間保持して焼結を行った。 次いで、このようにして得たSiCウィスカー/ S 
i 3 N4複合セラミックス焼結体をテトラクロロシ
ラン(SiCJl。)とNH3と過剰のH2ガスとの混
合気体(SiC文。:NH3:H2−3:4:15)中
1気圧(0、98MP a) 。 1250°Cにおいて1時間静置させることによって、
複合セラミックス焼結体の表面にSi3N4の被膜を形
成させた。 なお、このときの被膜の形成は、次の化学反応に基づく
気相化学反応(CVD)によるものであ1す る。 3SiCu4 +4NH3+excessH2+Si3
 N4 +12HCJj+excessH2この反応に
より形成されたSi3N4被膜の厚さは約1gmであり
、空孔や亀裂などといった欠陥は全く観察されない緻密
なSi3N4被膜であった。 このようにして表面被覆を施したSiCウィスカー/S
i3N4複合セラミックス焼結体をN2ガス圧力20M
Pa、温度1750°Cにおいて1時間保持して再焼結
を行った。 この再焼結によって得られた複合セラミックス焼結体の
密度は3.37g/cm’  (理論密度比99.3%
)であった。 また、抗折強度(3点曲げ)および破壊靭性値(SEP
B法)はそれぞれ830MPaおよび8 、1MP a
 拳iテあった。 実施例3 SiC粉末(ベータランダム・ウルトラファイン:イビ
デン製)84gに、B粉末1gとフェノール樹脂5gと
TiN粉末(粒径的1gm)10gを加え、有機溶剤ジ
オキサンを用いて100時間ボールミルを行った。 次いで、ボールミル後に実施例1と同じ要領で乾燥し、
乾燥した粉末を用いて圧粉成形体を作成したのち、フェ
ノール樹脂を炭化し、真空中で2100°cxo、sh
の焼結を行った。このようにした得られたTiN粒子/
 S i ’C複合セラミックス焼結体の密度は2.8
3g/Cm3 (理論密度比85.5%〕であった。 次に、この複合セラミックス焼結体の表面に実施例1と
同じ気相化学反応によってSiC被膜を形成させた。 続いて、このように表面被覆を施したTiN粒子/ S
 i C複合セラミックス焼結体をArガス圧力30M
Pa、温度2150℃において1時間保持して再焼結を
行った。 この再焼結によって得られたT i N粒子/SiC複
合セラミックス焼結体の密度は3.29g/am’  
(理論密度比99.3%)であった。 また、抗折強度(3点曲げ)および破壊靭性値(SEP
B法)はそれぞれ910MPaおよび5 、7MP a
−f;テあり、SiCウィスカーをSiC焼結体中に分
散させた実施例1の場合に比べて、TiN粒子をSiC
焼結体中に分散させたこの実施例3の方が高強度のもの
を得ることができた。 実施例4〜8.比較例1〜4 実施例1と同じ要領に基づいて作成したSiC被膜を有
するSiCウィスカー/ S i C複合セラミックス
焼結体をArガス圧力1〜100MPa、温度2100
°Cにおいて1時間保持して再焼結を行った。 この再焼結によって得られた比較例2〜4および実施例
4〜8の複合セラミックス焼結体および再焼結を行わな
い比較例1の複合セラミックス焼結体の密度、抗折強度
および破壊靭性値を測定したところ、第1表に示す結果
であった。 第1表に示した結果より明らかなように、理論密度比9
5%以上の強度の高い強靭な複合セラミ・ンクス焼結体
を作成するには、圧力5 M P a以上のArガスを
用いて再焼結することが著しく有効であることが認めら
れた。
(Means for Solving the Problems) The method for producing a silicon non-oxide ceramic sintered body according to the present invention is characterized in that the surface of the silicon non-oxide ceramic sintered body has the same composition as the main component of the sintered body. After forming a dense film mainly consisting of the components, the pressure was set to 5 MPa using a pressurizing gas.
It is characterized by a structure in which re-sintering is performed to a theoretical density ratio of 95% or more by heating and pressurizing in the above atmosphere, and the structure of the method for manufacturing such a ceramic sintered body overcomes the above-mentioned conventional problems. It is used as a means to solve the problem. In the method for manufacturing a ceramic sintered body according to the present invention, a ceramic sintered body mainly composed of SiC, a Si3N4
Ceramic sintered bodies are used that mainly contain SiC powder, Si3N4 powder, sintering aids, reinforcing fibers such as SiC whiskers, and reinforcing particles such as carbides and nitrides. For example, a pressureless sintered body (
The theoretical density ratio is 80 to 90%). The amount of these reinforcing fibers and reinforcing particles added is
For example, in the case of SiC whiskers, a compound with a content of 20 to 30% by volume is used, although it may vary depending on the type thereof. In addition, ceramic sintered bodies mainly composed of SiC and S
S on the surface of the ceramic sintered body mainly composed of i3N4.
When forming a dense film mainly composed of iC or a dense film mainly composed of Si3N4, vapor deposition methods (e.g.
Any suitable means such as chemical vapor deposition (CVD) can be used. The dense film in this case is Si
C, Si3 N4. It is preferable to use a material that is dense enough to be gas-impermeable and has a thickness of about several pm to prevent the passage of scum such as Ar and N2. Next, the dense film mainly composed of SiC and Si3N
After forming a dense film mainly composed of 4, it is resintered to a theoretical density ratio of 95% or more by heating and pressurizing it in an atmosphere with a pressure of 5 MPa or more using a pressurizing gas.
In this case, for example, hot isostatic pressure 1fa (HI
Re-sintering is carried out by P). (Function of the invention) In the method for manufacturing a ceramic sintered body according to the present invention, Si
After forming a dense gas-impermeable film mainly composed of SiC on the surface of a ceramic sintered body mainly composed of C, or after forming a gas-impermeable dense film mainly composed of Si3N4 on the surface of a ceramic sintered body mainly composed of Si3N4. After forming a dense, permeable film, it is heated and pressurized using a pressurizing gas in an atmosphere with a pressure of 5 MPa or higher to achieve a theoretical density ratio of 9.
Since the structure is such that the sintered body is re-sintered to a temperature of 5% or more, after re-sintering a sintered body with a theoretical density ratio of about 80 to 90%, it has a high density with a theoretical electric density ratio of 95% or more and has high strength. This results in a ceramic sintered body with excellent mechanical properties such as fracture toughness. By combining the pressureless sintering method, which can produce complex shapes, with hot isostatic pressing, which can produce similarly complex shapes, parts with high richness and complex shapes have been manufactured.
The dense, gas-impermeable coating formed on the surface of the sintered body before resintering corresponds to the capsule (container) used in conventional hot isostatic compression; This results in the omission of steps such as removing the capsule after molding and sintering, and finishing the surface of the sintered body. (Example) Example 1 1 g of B powder and 5 g of phenol resin were added to 74 g of SiC powder (Beta Lantum Skewer Ultra Fine, manufactured by Ibiten), and ball milling was performed for 80 hours using an organic solvent dioxane. The resulting mixture was then injected with SiC whiskers (SCW#
1-105-0.7S (manufactured by Tatemizu Kagaku) was added thereto, and ball milling was further performed for 20 hours. Next, the mixture mixed by a ball mill is mixed with liquid N2
After obtaining frozen granules by injecting into the solution, dioxane was removed by vacuum drying method. Subsequently, a powder compact was formed from the dried granules, and after carbonizing the phenol resin, sintering was performed at 2060° C. for 0.5 h in a vacuum. SiC whiskers thus obtained/SiC
The density of the composite ceramic sintered body is 2.70g/Cm'
(Theoretical density ratio: 84.1%) Next, this composite ceramic sintered body was placed in a mixed gas (CH30Si:H2=1:10) of methyltrichlorosilane CCH3Cl3S i) and excess N2 gas. 1 atm (0.98 MPa). A SiC film was formed on the surface of the composite ceramic sintered body by allowing it to stand at 1200° C. for 1 hour. Note that the film formation at this time is based on vapor phase chemical reaction (CVD) based on the following chemical reaction. CH30M3 Si+excessH2+SiC+3H
C1+excessH2 The thickness of the SiC film formed by this reaction is 1 to 2 g.
It was a dense SiC film with no defects such as pores or cracks observed. SiC whiskers with surface coating in this way/
S i C composite ceramic sintered body was heated to Ar gas pressure of 15
Re-sintering was performed by holding at MPa and temperature of 2100°C for 1 hour. The density of the composite ceramic sintered body obtained by this resintering is 3.17 g/cm3 (theoretical density ratio 98.8%)
Met. In addition, bending strength (3 points...lob) and fracture toughness value (SE
PB method) is 740 MPa and 6.8 MPa, respectively.
There were 51. Example 2 Si3N4 powder (Hl grade: manufactured by Stark) 65g
Add Y2O3 powder Log and A-bun 203 powder 5g to
Ball milling was performed using ethanol for 80 hours. The resulting mixture was then injected with SiC whiskers (SCW#
1-105-0.7S (manufactured by Tatemizu Kagaku) was added thereto, and ball milling was further performed for 20 hours. Next, the mixture obtained by the ball mill was spray-heated and dried to obtain a dry powder, and then this powder was compacted and
700°0. Sintering was performed by holding in N2 gas at 1 atm (0.98 MPa) for 1 hour. Then, the thus obtained SiC whiskers/S
i3 The N4 composite ceramic sintered body was heated at 1 atm (0.98 MPa) in a mixed gas of tetrachlorosilane (SiCJl.), NH3, and excess H2 gas (SiCJl.:NH3:H2-3:4:15). . By standing at 1250°C for 1 hour,
A Si3N4 film was formed on the surface of the composite ceramic sintered body. The film is formed at this time by vapor phase chemical reaction (CVD) based on the following chemical reaction. 3SiCu4 +4NH3+excessH2+Si3
N4 +12HCJj+excessH2 The thickness of the Si3N4 film formed by this reaction was about 1 gm, and it was a dense Si3N4 film in which no defects such as pores or cracks were observed. SiC whisker/S surface coated in this way
The i3N4 composite ceramic sintered body was heated to N2 gas pressure of 20M.
Re-sintering was carried out by holding at a temperature of 1750°C for 1 hour. The density of the composite ceramic sintered body obtained by this resintering is 3.37 g/cm' (99.3% of theoretical density ratio).
)Met. In addition, transverse strength (3-point bending) and fracture toughness value (SEP
Method B) is 830 MPa and 8,1 MPa, respectively.
There was a fist. Example 3 1 g of B powder, 5 g of phenol resin, and 10 g of TiN powder (particle size: 1 gm) were added to 84 g of SiC powder (Beta Random Ultra Fine, manufactured by Ibiden), and ball milled for 100 hours using an organic solvent dioxane. . Then, after ball milling, it was dried in the same manner as in Example 1,
After creating a powder compact using the dried powder, the phenolic resin was carbonized and heated at 2100°cxo, sh in vacuum.
was sintered. TiN particles thus obtained/
The density of the S i 'C composite ceramic sintered body is 2.8
3 g/Cm3 (theoretical density ratio 85.5%). Next, a SiC film was formed on the surface of this composite ceramic sintered body by the same gas phase chemical reaction as in Example 1. TiN particles with surface coating/S
i C composite ceramic sintered body under Ar gas pressure of 30M
Re-sintering was carried out by holding at a temperature of 2150° C. for 1 hour. The density of the T i N particle/SiC composite ceramic sintered body obtained by this resintering is 3.29 g/am'
(Theoretical density ratio 99.3%). In addition, transverse strength (3-point bending) and fracture toughness value (SEP
Method B) is 910 MPa and 5,7 MPa, respectively.
-f; With Te, compared to the case of Example 1 in which SiC whiskers were dispersed in the SiC sintered body, TiN particles were
In this Example 3, in which the particles were dispersed in the sintered body, higher strength could be obtained. Examples 4-8. Comparative Examples 1 to 4 A SiC whisker/SiC composite ceramic sintered body having a SiC film prepared in the same manner as in Example 1 was heated at an Ar gas pressure of 1 to 100 MPa and a temperature of 2100 MPa.
Re-sintering was carried out by holding at °C for 1 hour. Density, flexural strength, and fracture toughness of the composite ceramic sintered bodies of Comparative Examples 2 to 4 and Examples 4 to 8 obtained by this resintering, and the composite ceramic sintered body of Comparative Example 1 without resintering. When the values were measured, the results were shown in Table 1. As is clear from the results shown in Table 1, the theoretical density ratio 9
It has been found that resintering using Ar gas at a pressure of 5 MPa or more is extremely effective in producing a strong composite ceramic sintered body with a strength of 5% or more.

【発明の効果】【Effect of the invention】

本発明に係るセラミックス焼結体の製造方法は、SiC
を主体とするセラミックス焼結体の表面にSiCを主体
とする緻密な被膜を形成した後、あるいはSi3N4を
主体とするセラミックス焼結体の表面にSi3N4を主
体とする緻密な被膜を形成した後、加圧用ガスを用いて
圧力5MPa以上の雰囲気にて加熱・加圧することによ
り理論密度比95%以上に再焼結するようにしたもので
あるから、複雑な形状のものを得ることができるものの
緻密化が困難である常圧焼結法により得られた複合セラ
ミックス焼結体を同じく複雑な形状のものを得ることが
できる熱間等方圧圧縮によって最終部品形状に極めて近
い状態でしかも強度および破壊靭性などの機械的特性に
著しく優れたものとして得ることが可能であり、セラミ
ックス被膜は複合セラミックス焼結体と実質的に同等の
ものであるので再焼結後に後処理を施す必要がないもの
となる。このため、複雑形状を有していると共に高強度
・高靭性であることが要求されるうえに優れた量産性を
有していることが要求されるタービンロータなどのセラ
ミックス部品に対して十分有利に適用することができる
という著しく優れた効果がもたらされる。
The method for manufacturing a ceramic sintered body according to the present invention includes SiC
After forming a dense film mainly composed of SiC on the surface of a ceramic sintered body mainly composed of, or after forming a dense film mainly composed of Si3N4 on the surface of a ceramic sintered body mainly composed of Si3N4, Since it is resintered to a theoretical density ratio of 95% or more by heating and pressurizing it in an atmosphere with a pressure of 5 MPa or more using a pressurizing gas, it is possible to obtain products with complex shapes but with high density. Composite ceramic sintered bodies obtained by the pressureless sintering method, which is difficult to produce, can be made into complex shapes by hot isostatic compression in a state extremely close to the final part shape, yet with high strength and fracture. It is possible to obtain a product with extremely excellent mechanical properties such as toughness, and since the ceramic coating is substantially equivalent to a composite ceramic sintered body, there is no need for post-treatment after resintering. Become. This makes it highly advantageous for ceramic parts such as turbine rotors, which have complex shapes and require high strength and toughness, as well as excellent mass productivity. It brings about a remarkable effect that it can be applied to.

Claims (1)

【特許請求の範囲】[Claims] (1)珪素の非酸化物系セラミックス焼結 体の表面に該焼結体の主成分と同じ成分を主体とする緻
密な被膜を形成した後、加圧用ガスを用いて圧力5MP
a以上の雰囲気にて加熱・加圧することにより理論密度
比95%以上に再焼結することを特徴とする珪素の非酸
化物系セラミックス焼結体の製造方法。
(1) After forming a dense film mainly composed of the same components as the main components of the sintered body on the surface of a silicon non-oxide ceramic sintered body, a pressure of 5 MP is applied using a pressurizing gas.
1. A method for producing a non-oxide ceramic sintered body of silicon, which comprises resintering to a theoretical density ratio of 95% or more by heating and pressurizing in an atmosphere of at least A.
JP1132298A 1989-05-25 1989-05-25 Production of ceramic sintered compact Pending JPH02311363A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1132298A JPH02311363A (en) 1989-05-25 1989-05-25 Production of ceramic sintered compact

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1132298A JPH02311363A (en) 1989-05-25 1989-05-25 Production of ceramic sintered compact

Publications (1)

Publication Number Publication Date
JPH02311363A true JPH02311363A (en) 1990-12-26

Family

ID=15078024

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1132298A Pending JPH02311363A (en) 1989-05-25 1989-05-25 Production of ceramic sintered compact

Country Status (1)

Country Link
JP (1) JPH02311363A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999001405A1 (en) * 1997-07-02 1999-01-14 Nippon Pillar Packing Co., Ltd. SiC COMPOSITE AND METHOD OF PRODUCTION THEREOF

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999001405A1 (en) * 1997-07-02 1999-01-14 Nippon Pillar Packing Co., Ltd. SiC COMPOSITE AND METHOD OF PRODUCTION THEREOF

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