US4879079A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Formation of lanthanum aluminate
Assignee: Osram Sylvania Inc
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Filing: 1984-07-16
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Granted: 1989-11-07
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Expires: 2004-07-16
Abstract
Abstract A process is disclosed for reacting the oxides of lanthanum and aluminum.
Inventors
- 👤 Martin Y. Hsieh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:13
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/50; C01; C01F; C01F7/00; C04B35/01; C04B35/44
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
96 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) formimg an admixture of oxides of lanthanum and aluminum in a weight ratio of lanthanum oxide to aluminum oxide of about 12 to 1 to about 1 to 12 and (b) heating said admixture at a sufficient temperature and for a sufficient time to form a reacted material containing at least some of a lanthanum aluminum compound having an atomic ratio of lanthanum to aluminum of about 1 to 1.
Claim 2
Dependent Claim
96 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) formimg an admixture of oxides of lanthanum and aluminum in a weight ratio of lanthanum oxide to aluminum oxide of about 12 to 1 to about 1 to 12 and (b) heating said admixture at a sufficient temperature and for a sufficient time to form a reacted material containing at least some of a lanthanum aluminum compound having an atomic ratio of lanthanum to aluminum of about 1 to 1.
Claim 3
Dependent Claim
21 words
A process according to claim 1 wherein the atomic ratio of oxides of lanthanum and aluminum is about 1 to 1.
Claim 4
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 5
Dependent Claim
20 words
A process according to claim 1 wherein said admixture is heated for from about 9 hours to about 20 hours.
Claim 6
Dependent Claim
35 words
A process according to claim 1 wherein said reacted material consists essentially of at least about 35% by weight of a lanthanum aluminum compound having an atomic ratio of lanthanum to aluminum of about 1:1.
Claim 7
Dependent Claim
17 words
A process according to claim 1 wherein the process for producing silicon nitride bodies is slip casting.
Claim 8
Dependent Claim
17 words
A process according to claim 1 wherein the process for producing silicon nitride bodies is tape casting.
Claim 9
Dependent Claim
14 words
A process according to claim 1 wherein essentially all of the lanthanum is reacted.
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) | 1992-11-06 | 1993-05-08 | 1993-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-06 | 1997-05-08 | 1997-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-06 | 2001-05-08 | 2001-11-07 | $7700.00 | Window Closed / Lapsed |