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US4902653A
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Silicon nitride ceramic article
Assignee: Toshiba Corp
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Filing: 1988-06-06
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Granted: 1990-02-20
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Expires: 2008-06-06
Abstract
Abstract A sintered silicon nitride ceramic article excelling in high-temperature strength and experiencing only an insignificant decline of strength at elevated temperatures particularly up to 1,300° C. is produced by firing a ceramic mixture composed of not more than 10% by weight of the oxide of a rare earth element, not more than 10% by weight of at least one member selected from the group consisting of oxides, carbides, and silicides respectively of Hf, Ta, and Nb, optionally not more than 10% by weight of aluminum nitride, and the balance being silicon nitride.
Inventors
- 👤 Michiyasu Komatsu
- 👤 Hiroyasu Ohta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:11
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; C04B35/5935
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
59 words
A sintered silicon nitride ceramic article, consisting essentially of not more than 10% by weight (excluding the 0 content) of an oxide of a rare earth element, not more than 5% by weight (excluding the 0 content) of hafnium oxide, not more than 5% by weight (excluding the 0 content) of aluminum nitride, and the balance being silicon nitride.
Claim 2
Dependent Claim
59 words
A sintered silicon nitride ceramic article, consisting essentially of not more than 10% by weight (excluding the 0 content) of an oxide of a rare earth element, not more than 5% by weight (excluding the 0 content) of hafnium oxide, not more than 5% by weight (excluding the 0 content) of aluminum nitride, and the balance being silicon nitride.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-19 | 1993-08-21 | 1994-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-19 | 1997-08-21 | 1998-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-19 | 2001-08-21 | 2002-02-20 | $7700.00 | Window Closed / Lapsed |