JPH0372030B2 - - Google Patents
Info
- Publication number
- JPH0372030B2 JPH0372030B2 JP57151081A JP15108182A JPH0372030B2 JP H0372030 B2 JPH0372030 B2 JP H0372030B2 JP 57151081 A JP57151081 A JP 57151081A JP 15108182 A JP15108182 A JP 15108182A JP H0372030 B2 JPH0372030 B2 JP H0372030B2
- Authority
- JP
- Japan
- Prior art keywords
- alumina
- silicon carbide
- sintered body
- present
- hot
- 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
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 36
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 34
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 26
- 238000004519 manufacturing process Methods 0.000 claims description 11
- 238000010304 firing Methods 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 4
- 238000005452 bending Methods 0.000 description 10
- 239000000919 ceramic Substances 0.000 description 9
- 238000000034 method Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 239000002245 particle Substances 0.000 description 3
- 239000002131 composite material Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 238000007550 Rockwell hardness test Methods 0.000 description 1
- 229910021431 alpha silicon carbide Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006355 external stress Effects 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000013001 point bending Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Description
（発明の利用分野）
本発明はアルミナと炭化ケイ素を主成分とした
複合焼結体の製造方法に関し、より詳細にはアル
ミナセラミツクスの抗折強度及び硬度を向上する
ことができるアルミナ−炭化ケイ素系焼結体の製
造方法に関するものである。
（従来技術）
近年、アルミナセラミツクスは耐熱、耐摩耗、
耐薬品、耐絶縁及び物理的性質などに優れている
ため、電子部品材料、産機部品材料等幅広く賞用
され、例えば、産機部品分野ではベアリング、シ
ヤフト、軸受け等がアルミナセラミツクスに代替
されている。
（発明が解決しようとする問題点）
しかしながら、産機部品材料は抗折強度及び硬
度に著しく優れていることが望まれているが、ア
ルミナセラミツクスはこの点で満足し得るものと
は言い難く、過酷な用途に使用されるに十分な特
性値が未だ得られていなかつた。
例えば、耐火物としての用途に対して、アルミ
ナにカーボンや炭化ケイ素等を添加し、これを普
通焼結する方法などが知られているが、これらは
いずれも内部に気孔が多量に存在し、強度的にも
低いもので、産機部品等に用いるための特性をほ
とんど満足していないのが現状であつた。
（問題点を解決するための手段）
本発明者等は上記事情に鑑み、種々の実験を繰
り返した結果、アルミナに対し特定の比率で炭化
ケイ素を加え、これをホツトプレス焼成したとこ
ろ、抗折強度及び改良され、産機部品用として好
適な材料を提供できることを知見した。
本発明は上記知見に基づき、抗折強度及び硬度
の優れたアルミナ−炭化ケイ素系ホツトプレス焼
結体の製造方法を提供することを目的とするもの
である。
即ち、本発明は、アルミナと炭化ケイ素を主成
分とし、アルミナと炭化ケイ素の重量比率が45：
55乃至95：５の割合から成る混合体をホツトプレ
ス焼成したことを特徴とするものである。
以下、本発明を詳述する。
本発明の製造方法により得られる焼結体は主成
分がアルミナ及び炭化ケイ素から成り、その重量
比率（アルミナ：炭化ケイ素）が45：55乃至95：
５の割合からなる成るもので、炭化ケイ素成分の
比率が上記範囲より大きいと、ホツトプレスの
際、完全に緻密化するまでにアルミナが液相化し
てしまい、所望形状の焼結体が得られず、また逆
に炭化ケイ素の量が上記範囲より少ないと、複合
比による効果が得られず、アルミナ単味のホツト
プレス品と特性上、かわりがない。
抗折強度、硬度に加えて靭性特性の改良のため
には前記重量比率を70：30乃至90：10の割合に設
定することが好ましい。
本発明において用いるアルミナ及び炭化ケイ素
の粒径は概ねそれぞれ2.0μｍ以下及び5.0μｍ以下
であればよく、好ましくは両者とも1μｍ以下が
よい。
なお、炭化ケイ素は上記粉末の他、繊維体も使
用でき、これらはβ−炭化ケイ素を用いることも
できるが、安価で入手の容易なα−炭化ケイ素で
よい。
また、上記アルミナ及び炭化ケイ素を主成分と
しこれらに対し助剤として公知の材料を加えても
何差し支えない。
さらに、周知のことではあるが、アルミナと炭
化ケイ素とを主成分とした混合体を成形した後、
この成形体をホツトプレス焼成しても何ら差し支
えない。
上述した成分から成る混合体のホツトプレス焼
成は、焼成条件として温度約1800〜2000℃、圧力
約200〜500Kg／cm2がよい。
本発明の製造方法により得られるアルミナ−炭
化ケイ素系焼結体は従来のアルミナセラミツクス
中、特にアルミナのホツトプレス品と比べても抗
折強度及び硬度が顕著に改良され、その結果、大
きな外部応力が印加される産機部品として好適に
使用することができる。
これらの利点は、ホツトプレス焼成工程により
アルミナの焼結が先行するため、アルミナの焼結
とともに分散した炭化ケイ素粒子が凝集傾向を示
し、その結果、三次元的に複雑にからみ合つた炭
化ケイ素がアルミナ焼結体中にでき、これにより
炭化ケイ素がアルミナ焼結体に対し補強機能を有
することによるものと考えられる。
なお、本発明者等は光学顕微鏡により本発明の
製造方法により得られるアルミナ−炭化ケイ素系
焼結体を観察したところ、アルミナ焼結体中に複
雑にからみ合つた炭化ケイ素焼結体を確認した。
次に本発明を実施例に基づき詳細に説明する。
〔実施例〕
アルミナ粉末と炭化ケイ素粉末を第１表に示す
割合で混合し、44時間振動ミルで混合粉砕し、こ
の混合粉未をホツトプレス法で焼結した。この焼
成条件は圧力250Kg／cm2で、0.5時間加圧し、温度
は試料番号１で1600℃、炭化ケイ素成分比を大き
くするに従い、焼成温度を高くし、試料番号18で
2000℃とした。
そして、これらの焼結体の抗折強度、硬化及び
靭性を測定した。
抗折強度の測定はJISR1601の３点曲げ試験法
に、硬度の測定はロツクウエル硬度試験法（Ａス
ケール）に、そして靭性の測定は焼結体がマイク
ロクラツクの成長により破壊する際の臨界応力拡
大係数を焼結体の靭性特性としてS.E.N.B
（Singje Edge Notched Beam）法に、それぞれ
従つた。その結果は第１表に示す通りである。
(Field of Application of the Invention) The present invention relates to a method for manufacturing a composite sintered body mainly composed of alumina and silicon carbide, and more specifically to an alumina-silicon carbide system that can improve the bending strength and hardness of alumina ceramics. The present invention relates to a method for manufacturing a sintered body. (Conventional technology) In recent years, alumina ceramics have become heat resistant, wear resistant,
Due to its excellent chemical resistance, insulation resistance, and physical properties, alumina ceramics are widely used as materials for electronic parts and industrial machinery parts. There is. (Problems to be Solved by the Invention) However, it is desired that materials for industrial machinery parts have extremely high flexural strength and hardness, but alumina ceramics cannot be said to be satisfactory in this respect. Characteristic values sufficient for use in harsh applications have not yet been obtained. For example, for use as a refractory, there is a known method of adding carbon, silicon carbide, etc. to alumina and sintering it, but all of these methods have a large number of pores inside. Currently, it has low strength and hardly satisfies the characteristics required for use in industrial machinery parts. (Means for Solving the Problems) In view of the above circumstances, the inventors of the present invention repeatedly conducted various experiments, and found that silicon carbide was added to alumina at a specific ratio, and when this was hot-press fired, the bending strength was The inventors have also found that it is possible to provide a material that is improved and suitable for industrial machinery parts. Based on the above findings, the present invention aims to provide a method for producing an alumina-silicon carbide hot-pressed sintered body having excellent flexural strength and hardness. That is, the present invention has alumina and silicon carbide as main components, and the weight ratio of alumina and silicon carbide is 45:
It is characterized by hot press firing of a mixture having a ratio of 55 to 95:5. The present invention will be explained in detail below. The sintered body obtained by the manufacturing method of the present invention mainly consists of alumina and silicon carbide, and the weight ratio (alumina: silicon carbide) is 45:55 to 95:
If the ratio of the silicon carbide component is larger than the above range, the alumina will turn into a liquid phase before it is completely densified during hot pressing, making it impossible to obtain a sintered body with the desired shape. Conversely, if the amount of silicon carbide is less than the above range, the effect of the composite ratio cannot be obtained, and the properties are no different from those of a single alumina hot-pressed product. In order to improve toughness properties in addition to bending strength and hardness, it is preferable to set the weight ratio to 70:30 to 90:10. The particle sizes of alumina and silicon carbide used in the present invention may be approximately 2.0 μm or less and 5.0 μm or less, respectively, and preferably both are 1 μm or less. In addition to the above-mentioned powders, fibrous silicon carbide can also be used as silicon carbide, and although β-silicon carbide can also be used, α-silicon carbide, which is inexpensive and easily available, may be used. Furthermore, the alumina and silicon carbide mentioned above may be used as the main components, and known materials may be added thereto as auxiliaries without any problem. Furthermore, as is well known, after molding a mixture mainly composed of alumina and silicon carbide,
There is no problem even if this molded body is hot press fired. For hot-press firing of a mixture comprising the above-mentioned components, the firing conditions are preferably about 1800 to 2000° C. and about 200 to 500 kg/cm 2 pressure. The alumina-silicon carbide-based sintered body obtained by the production method of the present invention has significantly improved bending strength and hardness compared to conventional alumina ceramics, especially compared to hot-pressed alumina products, and as a result, has a large external stress. It can be suitably used as an industrial machine part to which voltage is applied. These advantages are due to the fact that the alumina is sintered in advance during the hot press firing process, and as the alumina is sintered, the dispersed silicon carbide particles tend to agglomerate, and as a result, the three-dimensionally intricately entangled silicon carbide becomes alumina. It is thought that this is because silicon carbide forms in the sintered body and thus has a reinforcing function for the alumina sintered body. In addition, when the present inventors observed the alumina-silicon carbide-based sintered body obtained by the manufacturing method of the present invention using an optical microscope, they confirmed that silicon carbide sintered bodies were intricately entangled in the alumina sintered body. . Next, the present invention will be explained in detail based on examples. [Example] Alumina powder and silicon carbide powder were mixed in the proportions shown in Table 1, mixed and ground in a vibrating mill for 44 hours, and the mixed powder was sintered by a hot press method. The firing conditions were a pressure of 250 kg/cm 2 for 0.5 hours, a temperature of 1600°C for sample number 1, and as the silicon carbide component ratio increased, the firing temperature was increased, and for sample number 18 the firing temperature was increased.
The temperature was 2000℃. Then, the bending strength, hardening, and toughness of these sintered bodies were measured. The bending strength is measured using the JISR1601 3-point bending test method, the hardness is measured using the Rockwell hardness test method (A scale), and the toughness is measured using the critical stress at which the sintered body breaks due to the growth of micro-cracks. SENB using the expansion factor as the toughness characteristic of the sintered body
(Singje Edge Notched Beam) law. The results are shown in Table 1.
【表】【table】
【表】
＊印を付した試料番号のものは本発明の範
囲外のものである。
表中、試料番号19は焼結中、アルミナが液相化
したため、所望形状の焼結体が得られず、試料番
号20では焼結しなかつた。また試料番号１では従
来の産機部品用アルミナセラミツクスの特性値を
比較例としてあげた。そこで第１表から明らかな
通り、アルミナと炭化ケイ素の重量比が70：30乃
至90：10の範囲の試料番号３〜７では抗折強度及
び硬度とともに靭性特性の増大傾向が確認でき、
炭化ケイ素の成分比が大きくなるとアルミナ及び
炭化ケイ素の粒径にもよるが、主に抗折強度の増
大傾向が確認できた。
本発明者等は産機部品の適用として高温強度特
性を調べるために、本発明の製造方法により得ら
れるアルミナ−炭化ケイ素系焼結体（試料番号２
〜18）を1000℃以上に加熱し、抗折強度を測定し
たところ、いずれもアルミナのホツトプレス品
（試料番号１）に比べ、高温高強度特性が認めら
れた。そこで飛躍的に高温高強度特性が向上した
代表例として、試料番号14の特性を図に示した。
図中、イ及びロはそれぞれ試料番号１及び14の特
性を示し、試料番号14の800℃での抗折強度は試
料番号１と比べ、約２倍大きくなつていることが
わかる。
（発明の効果）
以上の通り、本発明の製造方法により得られる
アルミナ−炭化ケイ素系焼結体は従来の産機部品
材料としてのアルミナセラミツクスよりも抗折強
度が著しく向上し、且つ硬度も改良され、加え
て、アルミナと炭化ケイ素の重量比が70：30乃至
90：10の範囲ではアルミナ単味のホツトプレス品
よりも靭性特性が向上されることが判明した。
更に、本発明の製造方法により得られるアルミ
ナ−炭化ケイ素系焼結体は従来の産機用アルミナ
セラミツクスに比べ、高温下でも顕著な高強度特
性の傾向が認められ、耐熱構造部品材料として優
れた適性を示すことがわかつた。
※図 図はアルミナセラミツクス及び本発明の製
造方法により得られるアルミナ−炭化ケイ素系焼
結体の抗折強度特性曲線を示すグラフの線図であ
る。[Table] Sample numbers marked with * are outside the scope of the present invention.
In the table, sample number 19 was unable to obtain a sintered body of the desired shape because the alumina turned into a liquid phase during sintering, and sample number 20 was not sintered. In addition, in sample number 1, the characteristic values of conventional alumina ceramics for industrial machinery parts are listed as a comparative example. Therefore, as is clear from Table 1, in sample numbers 3 to 7 where the weight ratio of alumina and silicon carbide was in the range of 70:30 to 90:10, it was confirmed that there was a tendency for the toughness properties to increase as well as the bending strength and hardness.
It was confirmed that as the component ratio of silicon carbide increases, the bending strength mainly tends to increase, although it depends on the particle sizes of alumina and silicon carbide. The present inventors investigated the high-temperature strength characteristics of industrial machinery parts using an alumina-silicon carbide-based sintered body (sample number 2) obtained by the manufacturing method of the present invention.
-18) were heated to 1000°C or higher and their flexural strength was measured, and both were found to have high strength properties at high temperatures compared to the hot-pressed alumina product (sample number 1). Therefore, the characteristics of sample number 14 are shown in the figure as a representative example of dramatically improved high-temperature, high-strength characteristics.
In the figure, A and B indicate the characteristics of sample numbers 1 and 14, respectively, and it can be seen that the bending strength of sample number 14 at 800°C is approximately twice as large as that of sample number 1. (Effects of the Invention) As described above, the alumina-silicon carbide-based sintered body obtained by the manufacturing method of the present invention has significantly improved flexural strength and hardness compared to alumina ceramics used as a conventional material for industrial machinery parts. In addition, the weight ratio of alumina and silicon carbide is 70:30 to
It was found that in the range of 90:10, the toughness properties were improved compared to hot-pressed products made of only alumina. Furthermore, the alumina-silicon carbide sintered body obtained by the production method of the present invention has a remarkable tendency to have high strength properties even at high temperatures compared to conventional alumina ceramics for industrial machinery, making it an excellent material for heat-resistant structural parts. I found out that it shows aptitude. *Figure The figure is a graph showing the bending strength characteristic curves of alumina ceramics and alumina-silicon carbide-based sintered bodies obtained by the manufacturing method of the present invention.
Claims (1)
ミナと炭化ケイ素との重量比率が45：55乃至95：
５の割合から成る混合体を、ホツトプレス焼成す
ることを特徴とするアルミナ−炭化ケイ素系焼結
体の製造方法。1 The main components are alumina and silicon carbide, and the weight ratio of alumina and silicon carbide is 45:55 to 95:
1. A method for producing an alumina-silicon carbide-based sintered body, which comprises hot press firing a mixture having a ratio of 5 to 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57151081A JPS5939766A (en) | 1982-08-30 | 1982-08-30 | Alumina-silicon carbide complex sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57151081A JPS5939766A (en) | 1982-08-30 | 1982-08-30 | Alumina-silicon carbide complex sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5939766A JPS5939766A (en) | 1984-03-05 |
| JPH0372030B2 true JPH0372030B2 (en) | 1991-11-15 |
Family
ID=15510897
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57151081A Granted JPS5939766A (en) | 1982-08-30 | 1982-08-30 | Alumina-silicon carbide complex sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5939766A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60210571A (en) * | 1984-03-31 | 1985-10-23 | イビデン株式会社 | Silicon carbide-containing alumina sintered body and manufacture |
| JPS61122164A (en) * | 1984-11-15 | 1986-06-10 | 株式会社リケン | Silicon carbide-alumina composite sintered body and manufacture |
| JPS61174165A (en) * | 1985-01-25 | 1986-08-05 | 株式会社 リケン | Alumina-silicon carbide heat-resistant composite sintered body and manufacture |
| IN167047B (en) * | 1985-03-14 | 1990-08-25 | Advanced Composite Materiales | |
| JPS63225574A (en) * | 1987-03-12 | 1988-09-20 | 東芝タンガロイ株式会社 | Ceramic sintered body for cutting tool member and manufacture |
| JP2507480B2 (en) * | 1987-09-30 | 1996-06-12 | 晧一 新原 | SiC-Al Lower 2 O Lower 3 Composite Sintered Body and Manufacturing Method Thereof |
| JP2507479B2 (en) * | 1987-09-30 | 1996-06-12 | 晧一 新原 | SiC-Al Lower 2 O Lower 3 Composite Sintered Body and Manufacturing Method Thereof |
| JP5093948B2 (en) * | 2001-09-11 | 2012-12-12 | 京セラ株式会社 | Magnetic head substrate and manufacturing method thereof |
| JP2006206376A (en) * | 2005-01-28 | 2006-08-10 | Ngk Spark Plug Co Ltd | Ceramic sintered compact, cutting insert and cutting tool |
-
1982
- 1982-08-30 JP JP57151081A patent/JPS5939766A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5939766A (en) | 1984-03-05 |
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