JPH0212893B2 - - Google Patents
Info
- Publication number
- JPH0212893B2 JPH0212893B2 JP56163280A JP16328081A JPH0212893B2 JP H0212893 B2 JPH0212893 B2 JP H0212893B2 JP 56163280 A JP56163280 A JP 56163280A JP 16328081 A JP16328081 A JP 16328081A JP H0212893 B2 JPH0212893 B2 JP H0212893B2
- Authority
- JP
- Japan
- Prior art keywords
- oxide ceramic
- sintering aid
- sintered body
- powder
- particle size
- 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
- 238000005245 sintering Methods 0.000 claims description 40
- 239000000843 powder Substances 0.000 claims description 30
- 229910052575 non-oxide ceramic Inorganic materials 0.000 claims description 23
- 239000011225 non-oxide ceramic Substances 0.000 claims description 23
- 239000002245 particle Substances 0.000 claims description 13
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 7
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 6
- 239000000919 ceramic Substances 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 4
- -1 LiO2 Inorganic materials 0.000 claims description 2
- 229910010413 TiO 2 Inorganic materials 0.000 claims 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims 1
- 229910052593 corundum Inorganic materials 0.000 claims 1
- 150000002484 inorganic compounds Chemical class 0.000 claims 1
- 229910010272 inorganic material Inorganic materials 0.000 claims 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims 1
- 239000002184 metal Substances 0.000 claims 1
- 229910052751 metal Inorganic materials 0.000 claims 1
- 229910052759 nickel Inorganic materials 0.000 claims 1
- 150000002894 organic compounds Chemical class 0.000 claims 1
- 230000003647 oxidation Effects 0.000 claims 1
- 238000007254 oxidation reaction Methods 0.000 claims 1
- 238000005979 thermal decomposition reaction Methods 0.000 claims 1
- 229910001845 yogo sapphire Inorganic materials 0.000 claims 1
- 230000007423 decrease Effects 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- 229910010271 silicon carbide Inorganic materials 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 229910003460 diamond Inorganic materials 0.000 description 2
- 239000010432 diamond Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000013001 point bending Methods 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- 239000012752 auxiliary agent Substances 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 238000001272 pressureless sintering Methods 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Description
この発明は、耐熱性セラミツクス焼結体、特に
非酸化物系セラミツクス焼結体に関するものであ
る。
耐熱性セラミツクスのなかでも窒化けい素や炭
化けい素等の非酸化物セラミツクスは耐熱性が特
にすぐれているため、高温ガスタービン、デイー
ゼルエンジンなどの構造材、部品材として有力で
あり、非常に関心をもつてその開発が進められて
いる。
耐熱性セラミツクス焼結体のこれら構造材への
使用に当つては、高温における物理的、化学的安
定性が要求される。特に高温における機械的特性
の高いことが望まれている。
ところが窒化けい素（Si3N4）や炭化けい素
（SiC）は、ともに共有結合性化合物であつて、
難焼結材とされている。従つてSi3N4やSiCはそ
れに単独に焼結させるのではなく、焼結助剤を数
％乃至数10％添加することにより低融点化合物を
形成させ焼結を促進させている。
例えばSi3N4の場合には、焼結助剤として
MgO、Al2O3、Y2O3などを５〜20％添加し、ホ
ツトプレスを行うことによつて理論密度に近い焼
結体が得られている。
しかしながら、このようにして得られる焼結体
は、高温における強度が不十分である。
即ち、焼結助剤として添加したMgO、Al2O3あ
るいはY2O3などは前記したように低融点化合物
を形成して焼結を促進せしめるという利点がある
反面、この低融点化合物が原因して高温における
強度が下るのである。
また焼結助剤の添加量が消えると、この低融点
化合物の融点がさらに下り、高温での強度低下が
より低温でおこることになる。
従つて焼結助剤の添加量としては、必要最少限
におさえることが高温強度維持のために重要であ
る。
しかしながら、一般に連結助剤は粒径0.5μ以上
の粉末で添加され、セラミツクス粉末とともにボ
ールミル等で混合して用いられるため、焼結助剤
の添加量を5vol％以下にすると、セラミツクス粉
末と焼結助剤との接触頻度が少くなり、焼結促進
効果が期待できない。
また混合状態における粉末の偏析も焼結助剤の
必要最少量を増加させる一因となるのである。
本発明者らは、上記した従来法の欠点を解決す
べく検討の結果、この発明に至つたものである。
即ち、この発明は非酸化物セラミツクス粉末、
例えばSi3N4粉末やSiC粉末に少量の焼結助剤を
用いて、しかも焼結性を損なうことなく、高温で
の強度劣化の少ない焼結体を提供しようとするも
のである。
詳しくは、焼結助剤として粒径500Å以下の超
微粉末を用いることにより、より少量の焼結助剤
で非酸化物セラミツクス粉末との均一混合粉末を
作り、その後型押し成形、焼結により非酸化物系
セラミツクス焼結体を得るものである。
即ち、焼結助剤の粒径を非酸化物セラミツクス
粉末に比べて小さくすることにより、非酸化物セ
ラミツクス粉末と焼結助剤の混合時に該非酸化物
セラミツクス粉末表面に焼結助剤をまぶした状態
にすることができ、少量の焼結助剤で非酸化物セ
ラミツクス粉末表面を覆うことができるのであ
る。
この場合の非酸化物セラミツクス粉末とコーテ
イングする焼結助剤との組合わせは、例えば非酸
化物セラミツクス粉末がSi3N4粉末の場合は、
MgO、Al2O3、Y2O3、LiO2、BeOなどの焼結助
剤のなかから選択するのが好ましく、また非酸化
物セラミツクス粉末としてSiCを用いる時には、
BN、Al2O3、Si3N4、AlN、B4C、Ｂ、Ｃなどの
焼結助剤のなかから選択することが好ましい。
そしてこの焼結助剤としては、それらのなかの
１種でもまた１種以上を混合して用いてもよい。
そして上記の焼結助剤微粉末の製造法として
は、特に限定されるものではないが、CVD法、
ガス蒸発法など一般的に知られている方法を用い
ればよい。
このような微粉末の粒径としては、検討の結
果、500Å以下であれば焼結性を損なわずにその
添加量を2vol％以下に減らし得ることが得められ
た。
また、この発明は上記のように超微粉末の焼結
助剤を用いることにより、非酸化物セラミツクス
粉末と焼結助剤との混合が均一に行え、従つて焼
結体の特性の均一度も向上することが確認され
た。
以下この発明を実施例により詳細に説明する。
実施例 １
平均粒径0.3μのSi3N4粉末と下記の第１表に示
す焼結助剤とを混合したのち、夫々2t／cm2の圧力
にて型押し成形して抗折試験片を作成した。
次いでこの各試験片をN2気流雰囲気中で1700
℃、30分の条件で常圧焼結を行つた。
得られた夫々の焼結体について＃400ダイヤモ
ンド砥石で研削仕上げをしたのち、20mmスパンの
３点曲げ試験を行つた。結果は第１表の通りであ
つた。
The present invention relates to a heat-resistant ceramic sintered body, particularly a non-oxide ceramic sintered body. Among heat-resistant ceramics, non-oxide ceramics such as silicon nitride and silicon carbide have particularly excellent heat resistance, and are therefore of great interest as structural and component materials for high-temperature gas turbines, diesel engines, etc. Its development is progressing. When using heat-resistant ceramic sintered bodies for these structural materials, physical and chemical stability at high temperatures is required. In particular, high mechanical properties at high temperatures are desired. However, silicon nitride (Si 3 N 4 ) and silicon carbide (SiC) are both covalent compounds.
It is considered to be a difficult-to-sinter material. Therefore, Si 3 N 4 and SiC are not sintered alone, but a sintering aid is added thereto in an amount of several percent to several tens of percent to form a low melting point compound and promote sintering. For example, in the case of Si 3 N 4 , it is used as a sintering aid.
By adding 5 to 20% of MgO, Al 2 O 3 , Y 2 O 3 and the like and performing hot pressing, a sintered body having a density close to the theoretical density has been obtained. However, the sintered body thus obtained has insufficient strength at high temperatures. That is, while MgO, Al 2 O 3 , Y 2 O 3 , etc. added as sintering aids have the advantage of forming low melting point compounds and accelerating sintering as described above, on the other hand, these low melting point compounds are the cause of sintering. As a result, the strength at high temperatures decreases. Furthermore, when the amount of sintering aid added disappears, the melting point of this low melting point compound further decreases, and the strength decrease at high temperatures occurs at lower temperatures. Therefore, it is important to keep the amount of the sintering aid added to the minimum necessary level in order to maintain high-temperature strength. However, in general, the sintering aid is added as a powder with a particle size of 0.5μ or more, and is mixed with the ceramic powder in a ball mill, etc., so if the amount of the sintering aid added is 5 vol% or less, the sintering aid will The frequency of contact with the auxiliary agent decreases, and no sintering promotion effect can be expected. Powder segregation in the mixed state also causes an increase in the required minimum amount of sintering aid. The present inventors have arrived at this invention as a result of studies to solve the above-described drawbacks of the conventional method. That is, this invention provides non-oxide ceramic powder,
For example, by using a small amount of sintering aid in Si 3 N 4 powder or SiC powder, the aim is to provide a sintered body with less deterioration in strength at high temperatures without impairing sinterability. Specifically, by using ultrafine powder with a particle size of 500 Å or less as a sintering aid, a uniform powder mixture with non-oxide ceramic powder can be made using a smaller amount of sintering aid, and then by stamping and sintering. A non-oxide ceramic sintered body is obtained. That is, by making the particle size of the sintering aid smaller than that of the non-oxide ceramic powder, the surface of the non-oxide ceramic powder is sprinkled with the sintering aid when the non-oxide ceramic powder and the sintering aid are mixed. The surface of the non-oxide ceramic powder can be covered with a small amount of sintering aid. In this case, the combination of the non-oxide ceramic powder and the coating sintering aid is, for example, when the non-oxide ceramic powder is Si 3 N 4 powder,
Sintering aids are preferably selected from among MgO, Al 2 O 3 , Y 2 O 3 , LiO 2 , BeO, etc., and when SiC is used as the non-oxide ceramic powder,
Preferably, the sintering aid is selected from among BN, Al 2 O 3 , Si 3 N 4 , AlN, B 4 C, B, C and the like. The sintering aid may be used alone or in combination of one or more of them. The method for producing the above-mentioned sintering aid fine powder is not particularly limited, but includes CVD method,
A commonly known method such as a gas evaporation method may be used. As a result of investigation, it was found that if the particle size of such fine powder is 500 Å or less, the amount added can be reduced to 2 vol % or less without impairing sinterability. Furthermore, by using the ultrafine powder sintering aid as described above, the present invention can uniformly mix the non-oxide ceramic powder and the sintering aid, thereby improving the uniformity of the properties of the sintered body. It was also confirmed that this improved. The present invention will be explained in detail below with reference to Examples. Example 1 After mixing Si 3 N 4 powder with an average particle size of 0.3 μ and the sintering aid shown in Table 1 below, each was pressed and molded at a pressure of 2 t/cm 2 to obtain a bending test piece. It was created. Each specimen was then heated for 1700 min in a N2 atmosphere.
Pressureless sintering was performed at ℃ for 30 minutes. After finishing each of the obtained sintered bodies with a #400 diamond grindstone, a three-point bending test with a span of 20 mm was conducted. The results were as shown in Table 1.
【表】
実施例 ２
平均粒径0.25μのSiC粉末に第２表に示す焼結助
剤を配合し、夫々を2t／cm2の圧力で型押し成形し
て抗折試験片を作成した。
次いでこの各試験片を200Kg／cm2の圧力で2000
℃１時間ホツトプレス焼結を行つた。
かくして得られた焼結体を＃400のダイヤモン
ド砥石で研削仕上げしたのち20mmスパンの３点曲
げ試験を行つたところ第２表の結果を得た。[Table] Example 2 Sintering aids shown in Table 2 were blended with SiC powder having an average particle size of 0.25μ, and each was pressed and molded at a pressure of 2t/cm 2 to prepare a bending test piece. Next, each test piece was heated at a pressure of 200Kg/ cm2 for 2000
Hot press sintering was performed at ℃ for 1 hour. After finishing the sintered body thus obtained by grinding it with a #400 diamond grindstone, a three-point bending test with a span of 20 mm was performed, and the results shown in Table 2 were obtained.
【表】
上表から焼結助剤の粒径が大きく、しかも配合
量が多いと、高温強度の低下が大であり（試料No.
７）、また粒径の大きい焼結助剤の量を減じても
高強度のものは得られない（試料No.８）。
これに対し、この発明のように焼結助剤の粒径
を小さくするならば、配合量少くても焼結でき、
また高温での強度低下も小さく、バラツキも小さ
い（ワイブル係数が大きい）ことが認められた。[Table] From the table above, it can be seen that when the particle size of the sintering aid is large and the amount of the sintering aid is large, the high temperature strength decreases significantly (Sample No.
7), and even if the amount of sintering aid with large particle size was reduced, high strength could not be obtained (sample No. 8). On the other hand, if the particle size of the sintering aid is made small as in this invention, sintering can be performed even with a small amount of compounding.
In addition, it was observed that the decrease in strength at high temperatures was small and the variation was small (the Weibull coefficient was large).
Claims (1)
非酸化物系セラミツクス焼結体を得るに際し、前
記セラミツクス粉末の焼結助剤として500Å以下
の粒子径を有する粉末を用いたことを特徴とする
非酸化物セラミツクス焼結体。 ２ 非酸化物セラミツクス粉末としてSi3N4を用
いることを特徴とする特許請求の範囲第１項記載
の非酸化物セラミツクス焼結体。 ３ 焼結助剤として500Å以下の粒子径を有する
MgO、Al2O3、Y2O3、LiO2、BeO、Fe2O3、
CaO、TiO2、NiO、Cr2O3等の粉末から選んだ少
なくとも１種以上を用いることを特徴とする特許
請求の範囲第２項記載の非酸化物セラミツクス焼
結体。 ４ 非酸化物セラミツクスとしてSiCを用いるこ
とを特徴とする特許請求の範囲第１項記載の非酸
化物セラミツクス焼結体。 ５ 焼結助剤として500Å以下の粒子径を有する
Al2O3、BN、AlN、Si3N4、B4C、Ｂ、Ｃ等の粉
末から選んだ少なくとも１種以上を用いることを
特徴とする特許請求項第４項記載の非酸化物セラ
ミツクス焼結体。 ６ 焼結助剤として酸化処理あるいは熱分解処理
を施し、500Å以下の粒子径を有するMgO、
Al2O3、Y2O3、LiO2、BeO、Fe2O3、CaO、
TiO2、NiO、Cr2O3等の酸化物粉末を生成する
Mg、Al、Ｙ、Li、Be、Fe、Ca、Ti、Ni、Cr等
の金属元素を含む有機あるいは無機化合物を少な
くとも１種以上を用いることを特徴とする特許請
求の範囲第２項記載の非酸化物セラミツクス焼結
体。[Scope of Claims] 1. When obtaining a non-oxide ceramic sintered body using non-oxide ceramic powder as the main material, a powder having a particle size of 500 Å or less is used as a sintering aid for the ceramic powder. A non-oxide ceramic sintered body characterized by: 2. The non-oxide ceramic sintered body according to claim 1, characterized in that Si 3 N 4 is used as the non-oxide ceramic powder. 3 Has a particle size of 500Å or less as a sintering aid
MgO , Al2O3 , Y2O3 , LiO2 , BeO, Fe2O3 ,
The non-oxide ceramic sintered body according to claim 2, characterized in that at least one selected from powders such as CaO, TiO 2 , NiO, Cr 2 O 3 is used. 4. The non-oxide ceramic sintered body according to claim 1, characterized in that SiC is used as the non-oxide ceramic. 5. Has a particle size of 500 Å or less as a sintering aid.
The non-oxide ceramic according to claim 4, characterized in that at least one selected from powders such as Al 2 O 3 , BN, AlN, Si 3 N 4 , B 4 C, B, and C is used. Sintered body. 6 MgO as a sintering aid that has been subjected to oxidation treatment or thermal decomposition treatment and has a particle size of 500 Å or less,
Al 2 O 3 , Y 2 O 3 , LiO 2 , BeO, Fe 2 O 3 , CaO,
Generates oxide powders such as TiO 2 , NiO, Cr 2 O 3 etc.
Claim 2, characterized in that at least one organic or inorganic compound containing a metal element such as Mg, Al, Y, Li, Be, Fe, Ca, Ti, Ni, or Cr is used. Non-oxide ceramic sintered body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56163280A JPS5864279A (en) | 1981-10-12 | 1981-10-12 | Non-oxide ceramics sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56163280A JPS5864279A (en) | 1981-10-12 | 1981-10-12 | Non-oxide ceramics sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5864279A JPS5864279A (en) | 1983-04-16 |
| JPH0212893B2 true JPH0212893B2 (en) | 1990-03-29 |
Family
ID=15770808
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56163280A Granted JPS5864279A (en) | 1981-10-12 | 1981-10-12 | Non-oxide ceramics sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5864279A (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59184771A (en) * | 1983-04-04 | 1984-10-20 | トヨタ自動車株式会社 | Manufacture of silicon nitride sintered body |
| JPS59217668A (en) * | 1983-05-26 | 1984-12-07 | 東海高熱工業株式会社 | Carbon ceramic resistor |
| JPS60145965A (en) * | 1984-01-06 | 1985-08-01 | 宇部興産株式会社 | Manufacture of silicon nitride sintered body |
| JPS6110069A (en) * | 1984-06-21 | 1986-01-17 | 京セラ株式会社 | High strength minute silicon nitride sintered body and manufacture |
| JPS6144770A (en) * | 1984-08-10 | 1986-03-04 | 宇部興産株式会社 | Manufacture of silicon nitride sintered body |
| JPS61163170A (en) * | 1985-01-14 | 1986-07-23 | トヨタ自動車株式会社 | Manufacture of si3n4 sintered body |
| JPS61178473A (en) * | 1985-02-01 | 1986-08-11 | トヨタ自動車株式会社 | Manufacture of si3n4 sintered body |
| JPH0672051B2 (en) * | 1985-03-30 | 1994-09-14 | 京セラ株式会社 | Silicon carbide sintered body and method for producing the same |
| JPS61286248A (en) * | 1985-06-10 | 1986-12-16 | Toshiba Corp | Retaining jig for sealing parts |
| JP2587854B2 (en) * | 1988-03-24 | 1997-03-05 | 日清製粉株式会社 | Method for producing aluminum nitride sintered body with improved thermal conductivity |
-
1981
- 1981-10-12 JP JP56163280A patent/JPS5864279A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5864279A (en) | 1983-04-16 |
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