Patent US4472476A successfully refreshed from Google Patents.
US4472476A
Expired / Lapsed
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Composite silicon carbide/silicon nitride coatings for carbon-carbon materials
Assignee: RTX Corp
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Filing: 1982-06-24
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Granted: 1984-09-18
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Expires: 2002-06-24
Abstract
Abstract A multilayer coating system for the protection of carbon-carbon composites is described. The coating includes an inner layer of SiC (produced by a conversion process in which Si is diffused into the carbon substrate) and an outer layer of CVD (chemically vapor deposited) Si 3 N 4 . Such a coating provides exceptional oxidation resistance, to 2500° F. (1371° C.) and above, for carbon-carbon materials. Optionally, preliminary coatings of CVD SiC or pyrolytic graphite can be applied prior to application of the inner layer of SiC.
Inventors
- 👤 Richard D. Veltri
- 👤 Francis S. Galasso
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:57
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B41/45; C04B41/52; C04B41/80; C04B41/81; C04B41/89; C23; C23C; C23C16/00; C23C16/02; C23C16/0272; D; D01; D01F; D01F11/00; D01F11/10; D01F11/12; D01F11/125; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24967; Y10T428/29; Y10T428/2913; Y10T428/2916; Y10T428/2918; Y10T428/30
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
68 words
A carbon-carbon composite article adapted to resist environmental degradation at elevated temperatures which comprises: a. a carbon-carbon substrate; b. a pack derived SiC coating integral with the substrate surface having a thickness of from about 0.5 to 30 mils; and c. a CVD applied layer of Si 3 N 4 on the outer surface of the SiC layer having a thickness of from about 3 to 30 mils.
Claim 2
Dependent Claim
68 words
A carbon-carbon composite article adapted to resist environmental degradation at elevated temperatures which comprises: a. a carbon-carbon substrate; b. a pack derived SiC coating integral with the substrate surface having a thickness of from about 0.5 to 30 mils; and c. a CVD applied layer of Si 3 N 4 on the outer surface of the SiC layer having a thickness of from about 3 to 30 mils.
Claim 3
Dependent Claim
87 words
A carbon-carbon composite article adapted to resist environmental degradation at elevated temperatures which comprises: a. a carbon-carbon substrate; b. a layer of pyrolytic graphite having a thickness of from about 1 to about 5 mils; c. a pack derived SiC coating integral with the substrate surface having a thickness of from about 0.5 to about 30 mils; and d. a CVD applied layer of Si 3 N 4 on the outer surface of the SiC layer having a thickness of from about 3 to about 30 mils.
Claim 4
Dependent Claim
87 words
A carbon-carbon composite article adapted to resist environmental degradation at elevated temperatures which comprises: a. a carbon-carbon substrate; b. a layer of pyrolytic graphite having a thickness of from about 1 to about 5 mils; c. a pack derived SiC coating integral with the substrate surface having a thickness of from about 0.5 to about 30 mils; and d. a CVD applied layer of Si 3 N 4 on the outer surface of the SiC layer having a thickness of from about 3 to about 30 mils.
Claim 5
Dependent Claim
88 words
A carbon-carbon composite article adapted to resist environmental degradation at elevated temperatures which comprises: a. a carbon-carbon substrate; b. a layer of CVD applied SiC having a thickness of from about 0.5 to about 5 mils; c. a pack derived SiC coating integral with the substrate surface having a thickness of from about 0.5 to about 30 mils; and d. a CVD applied layer of Si 3 N 4 on the outer surface of the SiC layer having a thickness of from about 3 to about 30 mils.
Claim 6
Dependent Claim
88 words
A carbon-carbon composite article adapted to resist environmental degradation at elevated temperatures which comprises: a. a carbon-carbon substrate; b. a layer of CVD applied SiC having a thickness of from about 0.5 to about 5 mils; c. a pack derived SiC coating integral with the substrate surface having a thickness of from about 0.5 to about 30 mils; and d. a CVD applied layer of Si 3 N 4 on the outer surface of the SiC layer having a thickness of from about 3 to about 30 mils.
Claim 7
Dependent Claim
24 words
An article as in claims 1, 2 or 3 in which the pack derived SiC coating contains a small but effective quantity of B.
Claim 8
Dependent Claim
25 words
An article as in claims 1, 2 or 3 in which the SiC coating has a thickness of from about 1 to about 10 mils.
Claim 9
Dependent Claim
28 words
An article as in claims 1, 2 or 3 in which the Si 3 N 4 coating has a thickness of from about 5 to about 20 mils.
Claim 10
Dependent Claim
27 words
An article as in claim 1 in which the pack derived SiC coating is derived from a pack which contains from about 0.1 to about 3% boron.
Claim 11
Dependent Claim
27 words
An article as in claim 2 in which the pack derived SiC coating is derived from a pack which contains from about 0.1 to about 3% boron.
Claim 12
Dependent Claim
27 words
An article as in claim 3 in which the pack derived SiC coating is derived from a pack which contains from about 0.1 to about 3% boron.
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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) | 1987-09-18 | 1988-03-19 | 1988-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-18 | 1992-03-19 | 1992-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-18 | 1996-03-19 | 1996-09-18 | $7700.00 | Window Closed / Lapsed |