Patent US2021491A successfully refreshed from Google Patents.
Patent US3960577A successfully refreshed from Google Patents.
US3960577A
Expired / Lapsed
US
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Dense polycrystalline silicon carbide
Assignee: General Electric Co
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Filing: 1974-01-08
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Granted: 1976-06-01
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Expires: 1994-01-08
Abstract
Abstract A dense silicon carbide material having improved electrically conducting properties is disclosed which is prepared by forming a homogeneous dispersion of silicon carbide, a sufficient amount of a boron containing additive, and 3.5-10.0% by weight of silicon nitride and hot pressing the dispersion at a sufficient temperature and pressure whereby a dense substantially nonporous ceramic is formed. The silicon carbide material can be machined by electrical discharge machining or by electrochemical machining.
Inventors
- 👤 Svante Prochazka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:44
CPC Classifications
H; H01; H01B; H01B1/00; H01B1/04; C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565; C04B35/575
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
113 words
A dense hot pressed electrically conducting silicon carbide ceramic body consisting essentially of silicon carbide, a boron additive selected from the group consisting of boron and boron carbide wherein the amount of the boron additive is equivalent to 0.3-3.0% by weight of boron, and sufficient nitrogen atoms accommodated in the lattice of said silicon carbide making said body electrically conducting with a room temperature resistivity ranging up to about 50 ohm centimeters, said boron additive being in solid solution with the silicon carbide, said ceramic body consisting of a fine grained substantially uniform microstructure, being substantially pore free, and having a density of at least 98% of the theoretical density for silicon carbide.
Claim 2
Dependent Claim
113 words
A dense hot pressed electrically conducting silicon carbide ceramic body consisting essentially of silicon carbide, a boron additive selected from the group consisting of boron and boron carbide wherein the amount of the boron additive is equivalent to 0.3-3.0% by weight of boron, and sufficient nitrogen atoms accommodated in the lattice of said silicon carbide making said body electrically conducting with a room temperature resistivity ranging up to about 50 ohm centimeters, said boron additive being in solid solution with the silicon carbide, said ceramic body consisting of a fine grained substantially uniform microstructure, being substantially pore free, and having a density of at least 98% of the theoretical density for silicon carbide.
Claim 3
Dependent Claim
11 words
The ceramic body of claim 1, wherein the additive is boron.
Claim 4
Dependent Claim
12 words
The ceramic body of claim 1, wherein the additive is boron carbide.
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) | 1979-06-01 | 1979-12-01 | 1980-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-01 | 1983-12-01 | 1984-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-01 | 1987-12-01 | 1988-06-01 | $7700.00 | Window Closed / Lapsed |