Claims
- 1. A method for producing aluminum nitride ceramic having a dense smooth surface layer possessing a surface roughness Ra of lower than 0.3 .mu.m and possessing no defect larger than 25 .mu.m on its surface, comprising
- applying a paste of aluminum nitride for said surface layer onto a surface of (i) a sintered article of aluminum nitride or (ii) a preform of aluminum nitride which is not yet sintered, to form an insulating layer, wherein said paste contains more than 50% by weight of aluminum nitride powder, and
- sintering said paste at a temperature of 1500 to 2100.degree. C., wherein if said preform is used, it is also sintered with said paste,
- said paste being applied such that the final surface layer has a thickness between 10 .mu.m and 250 .mu.m after sintering.
- 2. The method set forth in claim 1, wherein, after sintering, an outer surface of the resulting surface layer is polished.
- 3. The method set forth in claim 1, further comprising applying a metal layer on the surface layer.
- 4. The method set forth in claim 1, wherein the sintered article or preform contains more than 80% by weight of aluminium nitride.
- 5. The method set forth in claim 1, wherein the paste is applied onto a surface of said sintered article.
- 6. The method set forth in claim 1, wherein the paste is applied onto a surface of said preform of aluminium nitride.
- 7. The method set forth in claim 1, wherein the aluminium nitride powder has a particle size less than 10 .mu.m.
Priority Claims (4)
Number |
Date |
Country |
Kind |
5-085359 |
Mar 1993 |
JPX |
|
5-093714 |
Mar 1993 |
JPX |
|
5-157943 |
Jun 1993 |
JPX |
|
5-202684 |
Jul 1993 |
JPX |
|
Parent Case Info
This application is a continuation, of application Ser. No. 08/439,099, filed May 11. 1995 abandoned which is a divisional application of application Ser. No. 08/ 210,502, filed Mar. 18, 1994 now abandoned.
US Referenced Citations (8)
Foreign Referenced Citations (1)
Number |
Date |
Country |
0 374 825 |
Jun 1990 |
EPX |
Divisions (1)
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Number |
Date |
Country |
Parent |
210502 |
Mar 1994 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
439099 |
May 1995 |
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