Patent USRE30286E successfully refreshed from Google Patents.
USRE30286E
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing high density silicon carbide product
Assignee: Stemcor Corp
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Filing: 1979-03-19
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Granted: 1980-05-27
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Expires: 1999-03-19
Abstract
Abstract Disclosure is made of a high-density, high-strength silicon carbide ceramic material that is produced using a silicon carbide powder containing boron or boron-containing compound as a densification additive by the utilization of boron in the sintering atmosphere.
Inventors
- 👤 John A. Coppola
- 👤 Richard H. Smoak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:38
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565; C04B35/575
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
114 words
A method of sintering silicon carbide powders containing boron or boron-containing compounds as densification aids to produce a high density silicon carbide ceramic material which comprises the step of sintering such powders in an atmosphere containing boron, wherein the partial pressure of boron in the sintering atmosphere is equal to or greater than the equilibrium vapor pressure of the boron in the silicon carbide powder during sintering of said powder.[...]..Iadd., said partial pressure of boron in the sintering atmosphere being provided by boron from a boron-containing slurry or solution applied to the interior of the sintering chamber prior to sintering, or by the addition of a boron-containing gas into the chamber during sintering .Iaddend..
Claim 2
Independent Claim
114 words
A method of sintering silicon carbide powders containing boron or boron-containing compounds as densification aids to produce a high density silicon carbide ceramic material which comprises the step of sintering such powders in an atmosphere containing boron, wherein the partial pressure of boron in the sintering atmosphere is equal to or greater than the equilibrium vapor pressure of the boron in the silicon carbide powder during sintering of said powder.[...]..Iadd., said partial pressure of boron in the sintering atmosphere being provided by boron from a boron-containing slurry or solution applied to the interior of the sintering chamber prior to sintering, or by the addition of a boron-containing gas into the chamber during sintering .Iaddend..
Claim 3
Dependent Claim
25 words
The method of claim 1 wherein the silicon carbide containing powders include boron in an amount between about 0.1 and about 5.0 percent by weight.
Claim 4
Dependent Claim
14 words
The method of claim 1 wherein the atmosphere containing boron includes an inert gas.
Claim 5
Dependent Claim
11 words
The method of claim 3 wherein the inert gas is nitrogen.
Claim 6
Dependent Claim
11 words
The method of claim 3 wherein the inert gas is argon.
Claim 7
Dependent Claim
11 words
The method of claim 3 wherein the inert gas is helium.
Claim 8
Dependent Claim
16 words
The method of claim 1 wherein the boron in the atmosphere is introduced as boron.[.chloride.]. .Iadd.trichloride..Iaddend.
Claim 9
Dependent Claim
16 words
The method of claim 1 wherein the boron in the atmosphere is introduced as boron carbide.
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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) | 1983-05-27 | 1983-11-26 | 1984-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-05-27 | 1987-11-26 | 1988-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-05-27 | 1991-11-26 | 1992-05-27 | $7700.00 | Window Closed / Lapsed |