Patent US4388414A successfully refreshed from Google Patents.
US4388414A
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Thermally stable silicon nitride material
Assignee: Ceradyne Inc
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Filing: 1981-12-21
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Granted: 1983-06-14
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Expires: 2001-12-21
Abstract
Abstract A thermally stable, oxidation resistant ceramic Si 3 N 4 material is disclosed. The material has a substantially pure primary phase formed of substantially pure silicon nitride. A substantially pure secondary phase of the material is formed of a material selected from the group consisting essentially of Si 3 N 4 /SiO 2 /4Y 2 O 3 , Si 3 N 4 /SiO 2 /2Y 2 O 3 and Si 3 N 4 /4SiO 2 /5Y 2 O 3 . The primary phase may be in the form of individual grains and the secondary phase may be in the form of grain boundaries between the individual grains.
Inventors
- 👤 John A. Mangels
- 👤 John R. Baer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:06
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; C04B35/5935; C04B35/591
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
85 words
A thermally stable material which consists of: a substantially pure primary phase formed of substantially pure silicon nitride; and a substantially pure secondary phase formed of a material selected from the group consisting of Si 3 N 4 /SiO 2 /4Y 2 O 3 , Si 3 N 4 /SiO 2 /2Y 2 O 3 , Si 3 N 4 /4SiO 2 /5Y 2 O 3 , wherein said primary phase forms individual grains and said secondary phase forms grain boundaries between said individual grains.
Claim 2
Dependent Claim
85 words
A thermally stable material which consists of: a substantially pure primary phase formed of substantially pure silicon nitride; and a substantially pure secondary phase formed of a material selected from the group consisting of Si 3 N 4 /SiO 2 /4Y 2 O 3 , Si 3 N 4 /SiO 2 /2Y 2 O 3 , Si 3 N 4 /4SiO 2 /5Y 2 O 3 , wherein said primary phase forms individual grains and said secondary phase forms grain boundaries between said individual grains.
References Cited (Backward Citations)
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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) | 1986-06-13 | 1986-12-13 | 1987-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-13 | 1990-12-13 | 1991-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-13 | 1994-12-13 | 1995-06-14 | $7700.00 | Window Closed / Lapsed |