US4552851A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Formation of yttrium aluminate as sintering aid for silicon nitride bodies
Assignee: Osram Sylvania Inc
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Filing: 1984-05-02
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Granted: 1985-11-12
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Expires: 2004-05-02
Abstract
Abstract A process is disclosed for reacting oxides of yttrium and aluminum.
Inventors
- 👤 Martin Y. Hsieh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:41
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; C01; C01F; C01F17/00; C01F17/30; C01F17/32; C01F17/34
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
98 words
In a process for producing silicon nitride bodies wherein a sintering aid is used, the improvement comprising forming said sintering aid by a process comprising: (a) forming an admixture of the oxides of yttrium and aluminum in a weight ratio of yttrium to aluminum of from about 10 to 1 to about 1 to 10 and (b) heating said admixture at a sufficient temperature and for a sufficient time to form at least some of a yttrium aluminum compound having an atomic ratio of yttrium to aluminum of either about 2 to 1 or about 3 to 5.
Claim 2
Dependent Claim
98 words
In a process for producing silicon nitride bodies wherein a sintering aid is used, the improvement comprising forming said sintering aid by a process comprising: (a) forming an admixture of the oxides of yttrium and aluminum in a weight ratio of yttrium to aluminum of from about 10 to 1 to about 1 to 10 and (b) heating said admixture at a sufficient temperature and for a sufficient time to form at least some of a yttrium aluminum compound having an atomic ratio of yttrium to aluminum of either about 2 to 1 or about 3 to 5.
Claim 3
Dependent Claim
20 words
A process according to claim 1 wherein said admixture is heated at from about 1000° C. to about 1450° C.
Claim 4
Dependent Claim
20 words
A process according to claim 1 wherein said admixture is heated for from about 3 hours to about 5 hours.
Claim 5
Dependent Claim
22 words
A process according to claim 1 wherein said reacted material consists essentially of at least about 50% of a yttrium aluminum compound.
Claim 6
Dependent Claim
17 words
A process according to claim 1 wherein the process for producing silicon nitride bodies is slip casting.
Claim 7
Dependent Claim
17 words
A process according to claim 1 wherein the process for producing silicon nitride bodies is tape casting.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-11-11 | 1989-05-13 | 1989-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-11 | 1993-05-13 | 1993-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-11 | 1997-05-13 | 1997-11-12 | $7700.00 | Window Closed / Lapsed |