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US3821005A
Expired / Lapsed
US
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Densification of silicon nitride
Assignee: RTX Corp
•
Filing: 1973-05-18
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Granted: 1974-06-28
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Expires: 1993-05-18
Abstract
Abstract Novel sintering aids are added to silicon nitride powders to permit hot pressing to high density with superior strength retention at high temperatures.
Inventors
- 👤 G Layden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:34
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
18 words
An article according to claim 1 wherein: the modulus of rupture at 1,300*C. is at least 40,000 p.s.i.
Claim 2
Dependent Claim
15 words
An article according to claim 2 wherein: the article is resistant to oxidation at 1,300*C.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |