US4225356A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sintering of silicon nitride using Be additive
Assignee: General Electric Co
•
Filing: 1979-08-13
•
Granted: 1980-09-30
•
Expires: 1999-08-13
Abstract
Abstract A particulate dispersion of silicon nitride and beryllium additive is formed into a green body and sintered at a temperature ranging from about 1900 DEG C. to about 2200 DEG C. in a sintering atmosphere of nitrogen at superatmospheric pressure producing a sintered body with a density ranging from about 80% to about 100%.
Inventors
- 👤 Svante Prochazka
- 👤 Charles D. Greskovich
- 👤 Richard J. Charles
- 👤 Robert A. Giddings
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:49
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; C04B35/5935
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
123 words
An as-sintered polycrystalline silicon nitride product of complex shape of a preformed compact of particulate material, said as-sintered product having a density ranging from at least about 80% to about 100% of the theoretical density of silicon nitride, said as-sintered product consisting essentially of silicon nitride and beryllium, said silicon nitride ranging from the β-form to at least about 80% by weight β-form-20% by weight α-form based on the total amount of said silicon nitride, said beryllium ranging in amount from less than about 0.1% by weight to less than about 2.0% by weight of said silicon nitride, said as-sintered product according to X-ray diffraction analysis ranging from a single phase body to one comprised of a primary phase and a secondary phase.
Claim 2
Dependent Claim
123 words
An as-sintered polycrystalline silicon nitride product of complex shape of a preformed compact of particulate material, said as-sintered product having a density ranging from at least about 80% to about 100% of the theoretical density of silicon nitride, said as-sintered product consisting essentially of silicon nitride and beryllium, said silicon nitride ranging from the β-form to at least about 80% by weight β-form-20% by weight α-form based on the total amount of said silicon nitride, said beryllium ranging in amount from less than about 0.1% by weight to less than about 2.0% by weight of said silicon nitride, said as-sintered product according to X-ray diffraction analysis ranging from a single phase body to one comprised of a primary phase and a secondary phase.
Claim 3
Dependent Claim
19 words
An as-sintered product according to claim 1 which according to said X-ray diffraction analysis is a single phase body.
Claim 4
Dependent Claim
15 words
An as-sintered product according to claim 1 wherein said secondary phase is a beryllium-containing phase.
Claim 5
Dependent Claim
31 words
An as-sintered product according to claim 1 which contains oxygen in an amount ranging from less than about 1% by weight to less than about 5% by weight of said product.
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) | 1983-09-30 | 1984-03-31 | 1984-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-30 | 1988-03-31 | 1988-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-30 | 1992-03-31 | 1992-09-30 | $7700.00 | Window Closed / Lapsed |