JPS6140872A

JPS6140872A - Silicon nitride sintered body

Info

Publication number: JPS6140872A
Application number: JP59161883A
Authority: JP
Inventors: 吉田　進弘
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 1984-07-31
Filing date: 1984-07-31
Publication date: 1986-02-27
Also published as: JPH0532348B2

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】（産業上の利用分野）本発明は高強度窒化ケイ素質焼結体を得るに際し、焼結
時の反応による分解から生起する重量減少を少なくし、
焼成収縮量を低減し、寸法精度の向上をはかり、高温で
の強度劣化の少ない耐酸化性の良好な窒化ケイ素質焼結
体に関するものである。Detailed Description of the Invention (Industrial Application Field) The present invention reduces weight loss caused by decomposition due to reaction during sintering when obtaining a high-strength silicon nitride sintered body,
The present invention relates to a silicon nitride sintered body that reduces the amount of shrinkage during firing, improves dimensional accuracy, and has good oxidation resistance with little deterioration in strength at high temperatures.

（従来の技術）従来窒化ケイ素＜Ｓｉ３Ｎ、）の焼結には、焼結助剤と
してＭｇＯ１Ａ　１１０２　、Ｌ　ａ　ｚ　０３、Ｙ、
　Ｏ，、スピネル、ＣｒユＯＪ　等の酸化物が３〜２０
重量％添加されており、焼結は高温で該酸化物が窒化ケ
イ素（ＳｉａＮ４）と反応し、ケイ酸塩融液を生じ、窒
化ケイ素（Ｓ　ｉａ　Ｎ４　）が該融液に溶解し析出す
ることにより進行する。この際、該ケイ酸塩融液を生成
する反応においてＳｉＯが生成され、このＳｉＯの蒸気
圧が高いためにＳｉＯが焼成雰囲気中に揮散し、窒化ケ
イ素質焼結体の重量減少を生していた。(Prior art) Conventionally, in the sintering of silicon nitride <Si3N, MgO1A 1102, L az 03, Y,
Oxides such as O, spinel, Cr-OJ, etc. are 3 to 20
% by weight, and during sintering, the oxide reacts with silicon nitride (SiaN4) at high temperatures to produce a silicate melt, and silicon nitride (SiaN4) dissolves in the melt and precipitates. Proceed according to At this time, SiO is produced in the reaction that produces the silicate melt, and because the vapor pressure of this SiO is high, SiO evaporates into the firing atmosphere, causing a weight loss of the silicon nitride sintered body. Ta.

窒化ケイ素（ＳｉａＮ＜）の焼結時には窒化ケイ素（Ｓ
ｉａＮ＋）表面に不可避的に存在するシリカあるいは焼
結助剤として一般に添加される酸化物との間で、５ｔａ
Ｎ令＋ＳｉＯコ４ＳｉＯ↑＋２　Ｎ、ｊ　　・・・　（１）式に基づく
反応により分解し、重量減少を生じる。この分解量が大
きくなると窒化ケイ素質原料の焼結体への歩留りが低下
し、収縮量が大きくなり、焼結体の寸法精度の低下をも
たらしていた。When sintering silicon nitride (SiaN<), silicon nitride (S
iaN+) between the silica that inevitably exists on the surface or the oxide commonly added as a sintering aid,
N age+SiO4SiO↑+2 N, j... Decomposes by the reaction based on equation (1), resulting in weight loss. When the amount of decomposition increases, the yield of the silicon nitride raw material in the sintered body decreases, the amount of shrinkage increases, and the dimensional accuracy of the sintered body decreases.

（発明が解決しようとする問題点）この分解を抑制するために、従来焼結を高圧の窒素ガス
圧下で行う等の改良がなされているが、（１）式に示さ
れる反応はＳｉＯガスを注入したりＳｉＯガスを発生す
る組成物を焼成雰囲気中において同時焼成するなどして
ＳｉＯの分圧を高めることを同時にしないと完全に抑制
することはできず、また第ＶＩａ族系の酸化物添加によ
る分解抑制法では添加される第Ｖｉａ族系酸化物が高温
で■５ｉ３Ｎ＋を酸化し、更に５ｉｆｔの生成を助長し
ていた。また、該酸化物の特徴として高温で揮発する傾
向が強く、揮発による無効分を補い、分解抑制効果を持
たせるに十分な添加量が不確定であった。(Problem to be solved by the invention) In order to suppress this decomposition, improvements have been made in the past, such as performing sintering under high pressure of nitrogen gas, but the reaction shown in equation (1) It cannot be completely suppressed unless the partial pressure of SiO is simultaneously increased by injecting or simultaneously firing a composition that generates SiO gas in the firing atmosphere. In the decomposition suppression method, the added Group Via oxide oxidized 5i3N+ at high temperatures and further promoted the formation of 5ift. Furthermore, the oxide has a strong tendency to volatilize at high temperatures, and it has been unclear how much to add to compensate for the ineffectiveness due to volatilization and to have a decomposition-inhibiting effect.

（問題点を解決するための手段）本発明者は上記の現状に鑑み鋭意研究の結果、従来窒化
ケイ素の焼結に添加されていた酸化物焼結助剤の量を減
少し第Ｖｉａ族の金属を添加することにより、５ｉ０２
の生成が抑制されると共に高温の強度劣化を低減し、高
温酸化雰囲気中における耐食性が改善されることを見い
出した。(Means for Solving the Problems) In view of the above-mentioned current situation, the present inventor has conducted intensive research and has reduced the amount of the oxide sintering aid that was conventionally added to the sintering of silicon nitride. By adding metal, 5i02
It has been found that the formation of is suppressed, strength deterioration at high temperatures is reduced, and corrosion resistance in high-temperature oxidizing atmospheres is improved.

従って、本発明は窒化ケイ素と、公知の酸化物焼結助剤
との混合物１００重量部に、第ＶＩａ族の金属粉末０．
５〜５．５重量部添加したものを焼結して得られる窒化
ケイ素質焼結体を提供することにより、前記問題点を一
掃せんとするものである。Accordingly, the present invention combines 100 parts by weight of a mixture of silicon nitride and a known oxide sintering aid with 0.00 parts by weight of Group VIa metal powder.
The purpose is to eliminate the above-mentioned problems by providing a silicon nitride sintered body obtained by sintering a silicon nitride containing 5 to 5.5 parts by weight.

窒化ケイ素に添加される酸化物系焼結助剤を減少させ上
記混合物１００重量部に対し０．５〜５．５重量部の第
Ｖｉａ族の金属粉末を添加し、大気圧以上の含窒素雰囲
気中１５５０〜２２００６Ｃの間で焼結する場合、５ｉＯｚ　　＋第ＶＩａ族金属　”　　Ｓ　ｉ３Ｎ＋　
十第■ａ族酸窒化物の反応が生じ、ＳｉＯの生成を抑制する。なお、酸化物
系焼結助剤を減少させ窒化ケイ素に添加される第Ｖｉａ
族金属が０．５重量部未満であれば、ＳｉＯｘの未反応
物が生成し未反応５ｉ０２が（１）式に示される反応に
よりＳｉＯを生成し分解・重量減少を生起する。また第
ＶＩａ族金属の添加量が５．５重量部を超えると、未反
応の第Ｖｉａ族金属が焼結体表面に析出したり、焼結体
中に残留し、機械的特性を劣化する。またＳｉＯの蒸気
圧が高いため焼成時には焼成温度が高くなる程、雰囲気
圧力も高くしなければ分解を抑制できない。しかしなが
ら１５５０°Ｃ未満の焼成温度では焼結不十分となり、
２２００’Ｃを超える焼成温度では分解過多となり焼成
温度としては不適当である。斯くして焼結された本発明
の焼結体中には第■ａ族金属元素が０６１〜４．５重量
％含有されることとなる。The oxide sintering aid added to silicon nitride is reduced, 0.5 to 5.5 parts by weight of Group Via metal powder is added to 100 parts by weight of the above mixture, and a nitrogen-containing atmosphere at atmospheric pressure or higher is added. When sintering between 1550 and 22006C, 5iOz + Group VIa metal "S i3N+
A reaction of Group 11a oxynitride occurs, suppressing the production of SiO. Note that Via, which is added to silicon nitride to reduce the oxide-based sintering aid,
If the group metal is less than 0.5 parts by weight, unreacted SiOx is produced, and the unreacted 5i02 produces SiO by the reaction shown in equation (1), causing decomposition and weight loss. Furthermore, if the amount of Group VIa metal added exceeds 5.5 parts by weight, unreacted Group Via metal will precipitate on the surface of the sintered body or remain in the sintered body, deteriorating the mechanical properties. Further, since the vapor pressure of SiO is high, decomposition cannot be suppressed unless the atmospheric pressure is also increased as the firing temperature becomes higher. However, if the firing temperature is less than 1550°C, sintering will be insufficient.
Firing temperatures exceeding 2200'C result in excessive decomposition and are inappropriate as firing temperatures. The sintered body of the present invention thus sintered contains 0.61 to 4.5% by weight of the Group Ia metal element.

（実施例）本発明を実施例に基づき詳細に説明する。(Example) The present invention will be explained in detail based on examples.

窒化ケイ素質原料粉末に対しそれぞれ第１表に示す焼結
助剤と第Ｖｉａ族金属粉末を各割合に添加した混合粉末
を振動ミルにより１２０時間粉砕混合した後、バインダ
ーとしてパラフィンワックスを用いて造粒し、成形圧２
ｔ　／　ｃ　ｍ”にてＪＩＳ抗折片をプレス成形し、第
１表に示す試料Ｎ、ｏ、１〜１３の焼結体とした。この
うち試料Ｎ００７〜上記試料Ｎ０８１〜１３の焼結体そ
れぞれにつき成形体重量からの重量減の度合と、品温お
よび１３００°ＣにおけるＪＩＳ４点曲げ抗折強度およ
び１３００°Ｃで１０００時間経過後における焼結体の
酸化による重量増（ｍ　ｇ　／　ｃ　ｒｎ’　）の度合
を測定し、第１表の結果を得た。A mixed powder in which the sintering aid and Group Via metal powder shown in Table 1 were added to the silicon nitride raw material powder in various proportions was pulverized and mixed in a vibrating mill for 120 hours, and then manufactured using paraffin wax as a binder. Graining, molding pressure 2
JIS bending pieces were press-formed at t/cm" to obtain sintered bodies of samples N, o, 1 to 13 shown in Table 1. Among these, sintered bodies of samples N007 to above samples N081 to 13 were formed. For each, the degree of weight loss from the molded weight, the product temperature and JIS 4-point bending strength at 1300°C, and the weight increase due to oxidation of the sintered body after 1000 hours at 1300°C (mg/c rn ) was measured, and the results shown in Table 1 were obtained.

（ｙ・人−Ｆ　午口　ン試料Ｎ００１〜６が本発明の範囲内のものであり、窒化
ケイ素および焼結助剤の混合物１００重量部に対して第
Ｖｉａ族金属粉末を０．５〜５．５重量部の範囲で添加
したものを１５５０〜２２００′Ｃの温度で、大気圧以
上の含窒素雰囲気下で焼結して得られた焼結体は脱バイ
ンダーした成形体からの重量減が９．３％以内と優れて
おり、通常１０％以上であることからも第ＶＩａ族金属
添加により窒化ケイ素表面に不可避的に存在するＳｉＯ
２の分解が抑制されたこと、および焼結助剤等との反応
によるＳｉＯよの生成が抑制されたことと解される。ま
た、１３００″Ｃにおける抗折強度は焼結助剤にＭｇＯ
を含有する本発明の範囲内の試料Ｎｏ、１．２では常温
との強度劣化が最大８０．５％で、本発明の範囲外の試
料ＮＯ，１１では９５．３％となり、その他の本発明の
範囲内の試料Ｎｏ、３〜６では常温との強度劣化が最大
２４．５％で、本発明の範囲外の試料Ｎ００７〜１０お
よび１２．１３では常温との強度劣化が３３％以上であ
り、第Ｖｉａ族金属添加系の試料Ｎｏ、１〜６が優れて
いることが理解される。Samples N001 to 6 are within the scope of the present invention, in which 0.5 to 5 parts by weight of Group Via metal powder is added to 100 parts by weight of the mixture of silicon nitride and sintering aid. The sintered body obtained by sintering the additive in the range of .5 parts by weight at a temperature of 1550 to 2200'C in a nitrogen-containing atmosphere above atmospheric pressure shows no weight loss from the molded body from which the binder has been removed. SiO, which is unavoidably present on the silicon nitride surface due to the addition of Group VIa metals, is
This is understood to be due to the fact that the decomposition of 2 was suppressed and the generation of SiO due to the reaction with the sintering aid etc. was suppressed. In addition, the bending strength at 1300″C was determined by using MgO as a sintering aid.
Sample No. 1.2 within the scope of the present invention containing For samples No. 3 to 6 within the range of , the strength deterioration with respect to room temperature is a maximum of 24.5%, and in samples No. 007 to 10 and 12.13, which are outside the range of the present invention, the strength deterioration with respect to room temperature is 33% or more. It is understood that Group Via metal-added samples Nos. 1 to 6 are excellent.

更に酸化性テストにおける重量増が本発明の範囲内の試
料Ｎｏ、１〜６では５　、　３　ｍ　ｇ　／　ｃ　ｍ３
以下であることは大気中の酸素と反応し生成するｓｉｏ
、’　が該第Ｖｉａ族金属あるいは酸窒化物と反応し、
高融点の第Ｖｌａ族ケイ酸化合物を生成し、耐酸化性保
護膜を形成するためと理解される。Furthermore, the weight increase in the oxidation test was 5.3 mg/cm3 for samples Nos. 1 to 6, which were within the range of the present invention.
The following is the sio produced by reacting with oxygen in the atmosphere.
, ' reacts with the Group Via metal or oxynitride,
It is understood that this is because a Vla group silicate compound with a high melting point is produced and an oxidation-resistant protective film is formed.

試料Ｎｏ、１２および１３は耐酸化性は良好だが、重量
減が１０％以上で高温での強度劣化も最低３３％と大き
く使用に耐えない。Samples Nos. 12 and 13 have good oxidation resistance, but the weight loss is 10% or more and the strength deterioration at high temperatures is at least 33%, making them unusable.

〔発明の効果〕〔Effect of the invention〕

本発明の窒化ケイ素質焼結体は、酸化物焼結助剤を含む
窒化ケイ素粉末１００重量部に、Ｖｉａ族の金属粉末０
．５〜５．５重量部添加して焼結したものであり、この
Ｖｌａ族金属の添加により、−５ｉ０λの生成が抑制さ
れ、これにより高温での強度劣化が少なく耐酸化性の良
好な窒化ケイ素質焼結体が得られるのであり、本発明の
実益は頗る大である。The silicon nitride sintered body of the present invention is produced by adding 0 parts by weight of Via group metal powder to 100 parts by weight of silicon nitride powder containing an oxide sintering aid.
．． It is sintered with 5 to 5.5 parts by weight added, and the addition of this Vla group metal suppresses the formation of -5i0λ, making it a silicon nitride with less strength deterioration at high temperatures and good oxidation resistance. A quality sintered body can be obtained, and the practical benefits of the present invention are extremely large.

−以上一手続補正書（自発）１．事件の表示昭和５９年特許願第　１し１＆ちう号２、発明の名称窒化ケイ素質焼結体８、補正をする者事件との関係　出願人住　所　京都市山科区東野北井ノ上町６番地の２２名　
称　（６６８）京セラ株式会社代゛表者稲盛和夫４、代理人５、補正命令の日付　（自発）７、補正の内容明細書を下記の如く補正します。- Written amendment to the above procedure (voluntary) 1. Description of the case 1988 Patent Application No. 1 and No. 2, Name of the invention: Silicon nitride sintered body 8, Person making the amendment Relationship to the case Applicant Address: 6 Kitainoue-cho, Higashino, Yamashina-ku, Kyoto City 22 people
Name (668) Kyocera Corporation Representative Kazuo Inamori 4, Agent 5 Date of amendment order (voluntary) 7. We amend the detailed statement of amendment as follows.

（１）第８頁第７行目及び下から５行目［５ｉｎ２Ｊを
ｌ　ＳｉＯＪと補正します。(1) Page 8, line 7 and line 5 from the bottom [Correct 5in2J to 1 SiOJ.

（２）第５頁下から２行目「１〜６の実験例」を「１〜
６に対する実験例」と補正します。(2) On the second line from the bottom of page 5, change “Experimental Examples 1 to 6” to “1 to 6.”
6.Experimental example for 6"

（３）第６頁第５行目「ｃｑｌｄ＞Ｊを「（ダ／ｄ）」
と補正します。(3) Page 6, line 5 “cqld>J” (da/d)
I will correct it.

（４）第７頁を別添の第７頁と差し替えます。(4) Replace page 7 with the attached page 7.

（第１表　右から２槽目最上段第８行目ｒｃ１１ｆ／／
ｄ）」をｒ（ＩＩｖ／ｃｔ）Ｊと補正）（５）第８頁第
１１行目「５ｉｎ２Ｊを「シｐ」と補正します。(Table 1, 2nd tank from the right, top row, 8th row, rc11f//
d)" to r(IIv/ct)J) (5) Page 8, line 11, "5in2J is corrected to "ship".

（６）第９頁第８行目「５．８ｓＩ／ｃ１１」をｒ５．
８＃乙〆」と補正します。(6) Set "5.8sI/c11" on page 9, line 8 to r5.
8 # Otsu〆” is corrected.

（７）第９頁下から５行目１’−８ｉ０２Ｊ　をｉ”　
８ｉ０　Ｊと補正します。(7) 5th line from the bottom of page 9 1'-8i02J i”
Correct it as 8i0 J.

８、添付書類の目録（１）明細書第７頁（第１表）　　　　１通・−以上一8. List of attached documents (1) Page 7 of the specification (Table 1) 1 copy・-1 or more

Claims

【特許請求の範囲】[Claims]

１、窒化ケイ素（Ｓｉ＿３Ｎ＿４）と、公知の酸化物焼
結助剤との混合物１００重量部に、第VIａ族の金属粉末
０．５〜５．５重量部添加したものを焼結して得られる
窒化ケイ素質焼結体。1. Obtained by sintering 0.5 to 5.5 parts by weight of Group VIa metal powder to 100 parts by weight of a mixture of silicon nitride (Si_3N_4) and a known oxide sintering aid. Silicon nitride sintered body.