JPH0463030B2 - - Google Patents
Info
- Publication number
- JPH0463030B2 JPH0463030B2 JP59256835A JP25683584A JPH0463030B2 JP H0463030 B2 JPH0463030 B2 JP H0463030B2 JP 59256835 A JP59256835 A JP 59256835A JP 25683584 A JP25683584 A JP 25683584A JP H0463030 B2 JPH0463030 B2 JP H0463030B2
- Authority
- JP
- Japan
- Prior art keywords
- silicon nitride
- sintered body
- sintering
- sintered
- periodic table
- 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.)
- Expired - Lifetime
Links
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 37
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 36
- 238000005245 sintering Methods 0.000 claims description 26
- 238000004519 manufacturing process Methods 0.000 claims description 16
- 230000000737 periodic effect Effects 0.000 claims description 15
- 229910052751 metal Inorganic materials 0.000 claims description 11
- 150000004678 hydrides Chemical class 0.000 claims description 9
- 239000002184 metal Substances 0.000 claims description 9
- 150000004767 nitrides Chemical class 0.000 claims description 9
- 239000006104 solid solution Substances 0.000 claims description 9
- 150000001247 metal acetylides Chemical class 0.000 claims description 7
- 239000012298 atmosphere Substances 0.000 claims description 6
- 230000001590 oxidative effect Effects 0.000 claims description 5
- 239000011812 mixed powder Substances 0.000 claims description 4
- 150000002739 metals Chemical class 0.000 claims 2
- 238000000034 method Methods 0.000 description 21
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 19
- 229910052799 carbon Inorganic materials 0.000 description 12
- 150000001875 compounds Chemical class 0.000 description 10
- 239000000843 powder Substances 0.000 description 9
- 238000002156 mixing Methods 0.000 description 8
- 239000013078 crystal Substances 0.000 description 7
- 229910002804 graphite Inorganic materials 0.000 description 7
- 239000010439 graphite Substances 0.000 description 7
- 239000007858 starting material Substances 0.000 description 7
- 238000005520 cutting process Methods 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- 239000012535 impurity Substances 0.000 description 6
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 6
- 238000000465 moulding Methods 0.000 description 5
- 238000001513 hot isostatic pressing Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 3
- 229910010271 silicon carbide Inorganic materials 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- -1 ferrous metals Chemical class 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000007731 hot pressing Methods 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000007569 slipcasting Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910021417 amorphous silicon Inorganic materials 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 229910052792 caesium Inorganic materials 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 238000010574 gas phase reaction Methods 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 150000002602 lanthanoids Chemical class 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 238000001272 pressureless sintering Methods 0.000 description 1
- 229910052701 rubidium Inorganic materials 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 238000003746 solid phase reaction Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 229910052716 thallium Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Landscapes
- Ceramic Products (AREA)
Description
（産業上の利用分野）
本発明は、切削用工具、耐摩耗用工具並びに自
動車、航空機のエンジンを含めた各種部品及びタ
ービン用部品のような構造用部品、更には半導体
用のマウントとして適用できる窒化ケイ素基焼結
体の製造方法に関する。
（従来の技術）
窒化ケイ素は、共有結合性の高い化合物である
ために構成原子の自己拡散係数が小さく、又、高
温で分解及び蒸発したり、更にはイオン結晶や金
属結晶に比べて粒界エネルギーと表面エネルギー
の比が大きいので本質的に難焼結材料の１つとさ
れている。そのために、窒化ケイ素にMgO、
Al2O3、Y2O3、AlNなどの焼結助剤を加えて、
反応焼結法、ホツトプレス法又は熱間静水圧加圧
（HIP）法によつて焼結されている。
（発明が解決しようとする問題点）
窒化ケイ素焼結体の製造方法の内、無加圧焼結
法又は反応焼結法は、金型、スリツプキヤスト、
ラバープレスなどで成形した粉末成形体を黒鉛板
などに置いて焼結し、ホツトプレス法は黒鉛の成
形モールドの中に窒化ケイ素を主体とする混合粉
末を詰めて圧力及び温度を加えて焼結している。
これらの方法によつて得る焼結体を更に、緻密な
焼結体にする目的で黒鉛板又は黒鉛容器内でHIP
処理する方法がとられている。このように窒化ケ
イ素焼結体の焼結工程において、窒化ケイ素が黒
鉛と接触する場合、接触部の黒鉛表面に窒化ケイ
素粉末などの離型材を塗布して焼結中、炭素によ
る焼結体への浸炭及び炭化を防止している。しか
しながら得られる焼結体表面の窒化ケイ素粒子界
面近傍には炭化ケイ素が偏在しており、この炭化
ケイ素が窒化ケイ素基焼結体の強度を劣下させる
という問題がある。
本発明は、上記のような問題点を解決したもの
で、具体的には焼結工程において焼結体中へ浸炭
した炭素を炭素との親和力の大きい元素もしくは
化合物で吸着固溶もしくは化合させて窒化ケイ素
焼結体の強度を劣化させないようにした窒化ケイ
素基焼結体の製造方法の提供を目的とする。
（問題点を解決するための手段）
窒化ケイ素焼結体は、大別すると２種類あり、
その１つはβ型（高温型）である六方晶結晶構造
の焼結体であり、他の１つはα型（低温型）であ
る三方晶結晶構造を含む焼結体である。この内、
前者は、鋳鉄を切削する切削用工具として特に効
果があり、その他耐摩耗用工具又は自動車用エン
ジン部品にと実用化が試みられており、本発明者
らも特願昭57−146582などで提案している。これ
に対して後者は、鋼又は耐熱合金などを切削する
切削用工具として特に効果があり、本発明者らは
特願昭59−33758などで提案している。
本発明者らは、この特願昭57−146582、特願昭
59−33758などの提案に基づいて更に窒化ケイ素
焼結体の高靭性化の追究を行なつたところ焼結過
程中に気相及び液相を介して圧粉体中に侵入して
くる炭素成分が圧粉体を構成している窒化ケイ素
を主体とする各成分と反応して焼結体の欠陥とな
る化合物を形成し、焼結体の強度低下になること
を確認することによつて本発明を完成するに至つ
たものである。
すなわち、本発明の窒化ケイ素基焼結体の製造
方法は、窒化ケイ素と窒化ケイ素以外の添加物で
ある焼結助剤とを含有する混合粉末を真空中又は
非酸化性雰囲気中で無加圧もしくは加圧しながら
1500℃以上の温度により焼結する製造方法におい
て、前記焼結助剤が周期律表4a，5a族金属の水
素化物並びに周期律表4a，5a，6a族金属の亜化
学量論組成の炭化物、窒化物及びこれらの相互固
溶体の中の少なくとも１種を含有していることを
特徴とするものである。この本発明の窒化ケイ素
基焼結体の製造方法は、出発原料としてα−窒化
ケイ素、β−窒化ケイ素、非晶質窒化ケイ素及び
これらの混在した窒化ケイ素を必要により使用す
ることができ、この窒化ケイ素に周期律表1a族
のLi、Na、Ｋ、Rb、Cs、2a族のBe、Mg、Ca、
Sr、Ba、Ra、3a族のSc、Ｙ、ランタノイド、3b
族のＢ、Al、Ga、In、Tl、4b族のGeの酸化物、
窒化物、窒炭化物及びこれらの相互固溶体の中の
少なくとも１種と周期律表4a族のTi、Zr、Hf、
5a族のＶ、Nb、Taの水素化物並びに周期律表4a
族、5a族、6a族の亜化学量論組成の炭化物、窒
化物、炭酸化物、窒酸化物及びこれらの相互固溶
体の中の少なくとも１種とからなる粉末を混合容
器に必要量添加する。この混合容器としては、ス
テンレス製又はセラミツクス製もしくはステンレ
スに超硬合金又はゴムなどを内張したものを使用
でき、この容器にSi2N4系、ZrO2系セラミツクス
ボール、スチールボール、超硬合金製ボールもし
くは不純物の混入を防ぐために表面被覆したボー
ルを加えて乾式で混合粉砕したり、又はヘキサ
ン、アルコール、ベンゼン、アセトンなどの有機
溶剤もしくは水を混合容器に加えて湿式で混合粉
砕できる。こうして混合粉砕した粉末は、カーボ
ン又は黒鉛製の焼結用モールドに詰めて、真空又
は非酸化性雰囲気中でそのまま直接ホツトプレス
による高周波加圧焼結、通電加圧焼結又は非酸化
性雰囲気ガス、例えばN2雰囲気ガスによる加圧
焼結によつて焼結したり、混合粉砕した粉末を金
型成形、押出成形、スリツプキヤステイングによ
る成形又はラバープレスなどの液圧成形によつて
成形した成形体もしくはこの成形体を焼結温度よ
り低い温度で予備焼結した後機械加工した成形体
を真空中又は非酸化性雰囲気中で無加圧焼結（減
圧焼結も含む）あるいは雰囲気ガスで加圧しなが
ら焼結することもできる。また、このような方法
で１度焼結したものをHIP処理を行なつて焼結体
の緻密化の促進及び強度の向上もできる。焼結温
度は、出発原料粉末の種類又は配合成分もしくは
上記製造条件によつても異なるが1500〜1900℃の
温度で相対密度100％近傍の緻密な焼結体が得ら
れる。これらの製造条件の内、焼結体中に混在し
てくる不純物は、焼結工程の他には混合粉砕工程
から混入する度合が高く、不純物の種類としては
混合容器及びボールに含有している成分で、特に
鉄属金属及び周期律表4a、5a、6a族の炭化物、
窒化物、炭窒化物などがあり、この内、特に鉄属
金属が不純物として混入する場合は、焼結体の強
度低下の原因になるために１体積％以下にするこ
とが望ましく、用途によつては製造条件の厳選に
よつて鉄属金属の不純物を0.3体積％以下にする
必要がある。
（作 用）
本発明の窒化ケイ素基焼結体の製造方法は、出
発原料として炭素との親和力が窒化ケイ素よりも
大きい化合物である周期律表4a、5a族の水素化
物並びに周期律表4a、5a、6a族の亜化学量論組
成の炭化物、窒化物及びこれらの相互固溶体の中
の少なくとも１種を含有させるもので、これらの
水素化物や亜化学量論組成の化合物が出発原料
中、主として窒化ケイ素中に含有している不純物
炭素又は焼結工程で存在すカーボンモールド、カ
ーボン発熱体などカーボン材料とによつて気相も
しくは固相反応を起こし、高硬度でかつ、高融点
である周期律表4a、5a、6a族の炭化物、炭窒化
物あるいはこれらの相互固溶体として焼結体中に
均一に分散する。このために、本発明の窒化ケイ
素基焼結体の製造方法によつて得られる焼結体
は、炭化ケイ素又はケイ素と炭素を含有した化合
物など焼結体の欠陥の起点となる化合物が大幅に
減少し、逆に周期律表4a、5a、6a族の炭化物、
炭窒化物又はこれらの相互固溶体からなる分散相
として存在しているために高硬度で高靭性の焼結
体になる。出発原料中に用いる水素化物又は亜化
学量論組成の化合物の内、特に周期律表4a、5a
族の水素化物は、焼結工程での昇温過程中約300
℃〜400℃で水素を分解して、残つた金属成分の
活性を高くし、焼結反応中に侵入拡散してくる炭
素と容易に反応して化合物となることから水素化
物を出発原料とするのが望ましい。
本発明の窒化ケイ素基焼結体の製造方法は、六
方晶結晶構造からなる窒化ケイ素焼結体及び三方
晶結晶構造を含有する窒化ケイ素焼結体の両方に
応用できるけれども三方晶結晶構造を含有する窒
化ケイ素焼結体の高硬度及び高靭性への効果が著
しいことから三方晶結晶構造を含有する窒化ケイ
素焼結体の製造方法に応用するのが望ましい。こ
こで使用する周期律表4a、5a族の水素化物並び
に周期律表4a、5a、6a族の亜化学量論組成の炭
化物、窒化物及びこれらの相互固溶体の中の少な
くとも１種は、出発原料中の５〜50重量％含有す
ることが焼結体の分散強化による高靭性化から望
ましいものである。
ここで記載してきた亜化学量論組成とは、非化
学量論組成の中の金属元素が１に対して非金属元
素が１未満の比でなる化合物を示すものである。
（実施例）
実施例 １
平均粒径0.4μmのSi3N4（α率92％）と平均粒径
0.3〜2μmの各種粉末を使用して第１表の如く各
試料を配合し、この配合した各試料をヘキサン溶
媒中WC基超硬合金製ボールと共にウレタン内張
り容器の中で混合粉砕した。得られた混合粉末か
ら溶媒を蒸発除去後、BN粉末で被覆したカーボ
ンモールド中に充填し、N2ガスで炉内を置換後
100〜400Kg／cm2の成形圧力、1650℃〜1850℃の温
度、50〜90分の保持時間でホツトプレスにより焼
結した。このようにして得た試料の一部は、更に
N2ガス雰囲気中、1500〜1800気圧、1700〜1850
℃の条件でHIP処理した。各試料の焼結条件及び
得られた焼結体の硬度、抗折力及び破壊靭性値を
第２表に示す。
(Field of Industrial Application) The present invention can be applied to cutting tools, wear-resistant tools, various parts including automobile and aircraft engines, structural parts such as turbine parts, and furthermore, as a mount for semiconductors. The present invention relates to a method for manufacturing a silicon nitride-based sintered body. (Prior art) Silicon nitride is a highly covalent compound, so its constituent atoms have a small self-diffusion coefficient, and it also tends to decompose and evaporate at high temperatures, and is more prone to grain boundary formation than ionic crystals or metal crystals. Because it has a large ratio of energy to surface energy, it is considered to be one of the materials that is essentially difficult to sinter. For that purpose, MgO, silicon nitride,
By adding sintering aids such as Al 2 O 3 , Y 2 O 3 , AlN,
Sintered by reactive sintering, hot pressing, or hot isostatic pressing (HIP). (Problems to be Solved by the Invention) Among the methods for producing silicon nitride sintered bodies, the pressureless sintering method or the reaction sintering method requires molding, slip casting,
A powder compact formed using a rubber press or the like is placed on a graphite plate and sintered.In the hot press method, a mixed powder mainly composed of silicon nitride is packed into a graphite mold and sintered by applying pressure and temperature. ing.
The sintered compact obtained by these methods is further subjected to HIP in a graphite plate or graphite container for the purpose of making a dense sintered compact.
A method is being taken to process it. In this way, in the sintering process of silicon nitride sintered bodies, when silicon nitride comes into contact with graphite, a release agent such as silicon nitride powder is applied to the graphite surface in the contact area, and during sintering, the carbon sintered body is released. Prevents carburization and carbonization. However, there is a problem in that silicon carbide is unevenly distributed near the silicon nitride particle interface on the surface of the obtained sintered body, and this silicon carbide deteriorates the strength of the silicon nitride-based sintered body. The present invention solves the above-mentioned problems. Specifically, in the sintering process, carbon carburized into a sintered body is adsorbed into a solid solution or combined with an element or compound that has a high affinity with carbon. An object of the present invention is to provide a method for manufacturing a silicon nitride-based sintered body that does not deteriorate the strength of the silicon nitride sintered body. (Means for solving the problem) There are two types of silicon nitride sintered bodies:
One of them is a sintered body having a hexagonal crystal structure which is β type (high temperature type), and the other is a sintered body having a trigonal crystal structure which is α type (low temperature type). Of these,
The former is particularly effective as a cutting tool for cutting cast iron, and attempts have been made to put it into practical use as other wear-resistant tools or automobile engine parts, and the present inventors also proposed it in Japanese Patent Application No. 146582/1983. are doing. On the other hand, the latter is particularly effective as a cutting tool for cutting steel or heat-resistant alloys, and the present inventors have proposed it in Japanese Patent Application No. 59-33758. The inventors of the present invention have submitted this patent application
59-33758, we further investigated how to improve the toughness of silicon nitride sintered bodies, and found that carbon components invaded into the compact through the gas and liquid phases during the sintering process. This study was conducted by confirming that the powder reacts with the various components, mainly silicon nitride, that make up the green compact, forming compounds that cause defects in the sintered compact, resulting in a decrease in the strength of the sintered compact. This led to the completion of the invention. In other words, the method for producing a silicon nitride-based sintered body of the present invention is to process a mixed powder containing silicon nitride and a sintering aid, which is an additive other than silicon nitride, in a vacuum or in a non-oxidizing atmosphere without pressure. Or while applying pressure
In the manufacturing method in which sintering is performed at a temperature of 1500° C. or higher, the sintering aid is a hydride of a metal of group 4a or 5a of the periodic table, or a carbide of a substoichiometric composition of a metal of group 4a, 5a or 6a of the periodic table, It is characterized by containing at least one of nitrides and mutual solid solution thereof. In the method for producing a silicon nitride-based sintered body of the present invention, α-silicon nitride, β-silicon nitride, amorphous silicon nitride, and silicon nitride in a mixture thereof can be used as a starting material, if necessary. Silicon nitride contains Li, Na, K, Rb, Cs from group 1a of the periodic table, Be, Mg, Ca from group 2a,
Sr, Ba, Ra, 3a group Sc, Y, lanthanoid, 3b
Group B, Al, Ga, In, Tl, group 4b Ge oxides,
At least one of nitrides, nitrides, and mutual solid solutions thereof, and Ti, Zr, Hf of group 4a of the periodic table,
Hydride of V, Nb, Ta of Group 5a and Periodic Table 4a
A required amount of powder consisting of at least one of substoichiometric carbides, nitrides, carbonates, nitrides, and mutual solid solutions of these groups is added to a mixing vessel. This mixing container can be made of stainless steel or ceramics, or stainless steel lined with cemented carbide or rubber, and Si 2 N 4 ceramic balls, ZrO 2 ceramic balls, steel balls, cemented carbide, etc. can be used as the mixing container. Mixing and pulverization can be carried out in a dry manner by adding manufactured balls or balls whose surface is coated to prevent contamination by impurities, or wet mixing and pulverization by adding an organic solvent such as hexane, alcohol, benzene, acetone, etc. or water to a mixing container. The thus mixed and pulverized powder is packed into a sintering mold made of carbon or graphite, and directly subjected to high-frequency pressure sintering using a hot press in a vacuum or non-oxidizing atmosphere, electrification pressure sintering, or non-oxidizing atmosphere gas. For example, a molded body that is sintered by pressure sintering using N2 atmosphere gas, or molded by molding mixed and pulverized powder by die molding, extrusion molding, slip casting, or hydraulic molding such as a rubber press. Alternatively, after pre-sintering this compact at a temperature lower than the sintering temperature, the machined compact is sintered under no pressure (including reduced pressure sintering) in vacuum or in a non-oxidizing atmosphere, or pressurized with atmospheric gas. It can also be sintered. Further, by performing HIP treatment on a material that has been sintered once using this method, it is possible to promote densification and improve the strength of the sintered material. Although the sintering temperature varies depending on the type of starting material powder, the blended components, or the above manufacturing conditions, a dense sintered body with a relative density of approximately 100% can be obtained at a temperature of 1500 to 1900°C. Among these manufacturing conditions, impurities mixed into the sintered body are likely to be mixed in from the mixing and crushing process in addition to the sintering process, and the types of impurities are those contained in the mixing container and balls. Ingredients, especially ferrous metals and carbides of groups 4a, 5a and 6a of the periodic table,
There are nitrides, carbonitrides, etc. Among these, when ferrous metals are mixed as impurities, it is desirable to reduce the amount to 1% by volume or less, as it may cause a decrease in the strength of the sintered body. Therefore, it is necessary to carefully select manufacturing conditions to reduce ferrous metal impurities to 0.3% by volume or less. (Function) The method for producing a silicon nitride-based sintered body of the present invention uses as starting materials hydrides of groups 4a and 5a of the periodic table, which are compounds having a greater affinity with carbon than silicon nitride, as well as hydrides of groups 4a and 5a of the periodic table. This method contains at least one of substoichiometric carbides, nitrides, and mutual solid solutions of Groups 5a and 6a, and these hydrides and substoichiometric compounds are the main components in the starting materials. A periodic material that causes a gas phase or solid phase reaction with impurity carbon contained in silicon nitride or carbon materials such as carbon molds and carbon heating elements present in the sintering process, and has high hardness and a high melting point. The carbides and carbonitrides of Tables 4a, 5a, and 6a groups or their mutual solid solutions are uniformly dispersed in the sintered body. For this reason, the sintered body obtained by the method for producing a silicon nitride-based sintered body of the present invention has a large amount of compounds that can cause defects in the sintered body, such as silicon carbide or compounds containing silicon and carbon. Carbides of groups 4a, 5a, 6a of the periodic table, which decrease and conversely
Since it exists as a dispersed phase consisting of carbonitrides or mutual solid solution thereof, the sintered body has high hardness and high toughness. Among the hydrides or substoichiometric compounds used in the starting materials, especially 4a and 5a of the periodic table
During the heating process during the sintering process, the hydrides of the group 300
Hydrogen is used as a starting material because it decomposes hydrogen at temperatures between ℃ and 400℃, increases the activity of the remaining metal components, and easily reacts with the carbon that invades and diffuses during the sintering reaction to form a compound. is desirable. The method for producing a silicon nitride-based sintered body of the present invention can be applied to both a silicon nitride sintered body having a hexagonal crystal structure and a silicon nitride sintered body containing a trigonal crystal structure. Since this method has a remarkable effect on the hardness and toughness of silicon nitride sintered bodies, it is desirable to apply it to a method for manufacturing silicon nitride sintered bodies containing a trigonal crystal structure. At least one of the hydrides of Groups 4a and 5a of the Periodic Table, the substoichiometric carbides and nitrides of Groups 4a, 5a, and 6a of the Periodic Table, and their mutual solid solution used here is a starting material. It is desirable that the content be 5 to 50% by weight in order to improve the toughness of the sintered body through dispersion strengthening. The substoichiometric composition described herein refers to a compound in which the ratio of non-metallic elements to one metallic element in the non-stoichiometric composition is less than one. (Example) Example 1 Si 3 N 4 with an average particle size of 0.4 μm (α rate 92%) and the average particle size
Each sample was blended using various powders of 0.3 to 2 μm as shown in Table 1, and each of the blended samples was mixed and ground in a urethane-lined container with WC-based cemented carbide balls in a hexane solvent. After removing the solvent from the obtained mixed powder by evaporation, it was filled into a carbon mold coated with BN powder, and the inside of the furnace was replaced with N2 gas.
Sintering was carried out by hot pressing at a molding pressure of 100-400 Kg/cm 2 , a temperature of 1650°C-1850°C, and a holding time of 50-90 minutes. Some of the samples obtained in this way were further
In N2 gas atmosphere, 1500-1800 atm, 1700-1850
HIP treatment was performed at ℃. Table 2 shows the sintering conditions for each sample and the hardness, transverse rupture strength, and fracture toughness values of the obtained sintered bodies.
【表】【table】
【表】【table】
【表】
（発明の効果）
以上の結果、本発明の窒化ケイ素基焼結体の製
造方法は、易焼結性があつて緻密な焼結体が得ら
れやすく、しかも得られる焼結体が高硬度で高靭
性であることから切削用工具部品のような苛酷な
用途からボール、ガイドブツシユ、ロール、ゲー
ジ類、バルブ、ノズル、メカニカルシールなどの
耐摩耗用部品、又はタービン部品、自動車エンジ
ン部品などの構造用部品、更には窒化ケイ素の高
熱伝導性及び高電気絶縁性を利用して半導体用の
マウントとしても応用できるもので産業上有用な
窒化ケイ素基焼結体の製造方法である。[Table] (Effects of the Invention) As a result of the above, the method for producing a silicon nitride-based sintered body of the present invention has easy sinterability and is easy to obtain a dense sintered body. Due to its high hardness and toughness, it can be used in harsh applications such as cutting tool parts, as well as wear-resistant parts such as balls, guide bushes, rolls, gauges, valves, nozzles, mechanical seals, turbine parts, and automobile engine parts. This is an industrially useful method for producing a silicon nitride-based sintered body, which can be applied to structural parts, and even as semiconductor mounts by utilizing the high thermal conductivity and high electrical insulation properties of silicon nitride.
Claims (1)
を真空中又は非酸化性雰囲気中で無加圧もしくは
加圧しながら1500℃以上の温度により焼結する製
造方法において、前記焼結助剤が周期律表4a，
5a族金属の水素化物並びに周期律表4a，5a，6a
族金属の亜化学量論組成の炭化物、窒化物及びこ
れらの相互固溶体の中の少なくとも１種を含有し
ていることを特徴とする窒化ケイ素基焼結体の製
造方法。1. In a manufacturing method in which a mixed powder containing silicon nitride and a sintering aid is sintered at a temperature of 1500°C or higher in vacuum or in a non-oxidizing atmosphere without or with pressure, the sintering aid is periodic table 4a,
Hydride of group 5a metals and periodic table 4a, 5a, 6a
1. A method for producing a silicon nitride-based sintered body, characterized in that it contains at least one of substoichiometric carbides, nitrides, and mutual solid solutions of group metals.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59256835A JPS61136963A (en) | 1984-12-05 | 1984-12-05 | Manufacture of silicon nitride base sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59256835A JPS61136963A (en) | 1984-12-05 | 1984-12-05 | Manufacture of silicon nitride base sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61136963A JPS61136963A (en) | 1986-06-24 |
| JPH0463030B2 true JPH0463030B2 (en) | 1992-10-08 |
Family
ID=17298084
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59256835A Granted JPS61136963A (en) | 1984-12-05 | 1984-12-05 | Manufacture of silicon nitride base sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61136963A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3889536B2 (en) | 1999-10-29 | 2007-03-07 | 日本特殊陶業株式会社 | Ceramic heater, method for manufacturing the same, and glow plug including the ceramic heater |
| JP4497787B2 (en) * | 2002-04-04 | 2010-07-07 | 株式会社東芝 | Rolling ball |
| JP5295983B2 (en) * | 2010-01-12 | 2013-09-18 | 株式会社東芝 | Method for producing wear-resistant member made of silicon nitride |
-
1984
- 1984-12-05 JP JP59256835A patent/JPS61136963A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61136963A (en) | 1986-06-24 |
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