US4661369A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-destructive evaluation method for coated carbon-carbon composites
Assignee: United States, AS REPRESENTED BY SECRERTARY OF AIR FORCE
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Filing: 1985-09-05
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Granted: 1987-04-28
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Expires: 2005-09-05
Abstract
Abstract A non-destructive technique for detecting and repairing surface flaws in the silicon carbide oxidation resistant coating of a carbon-carbon composite. The surface of the composite is treated with a test liquid consisting essentially of a carrier fluid, a particulate pigment and a finely divided borosilicate glass, or a mixture of silicon dioxide and boron oxide, containing 0.25 to 8 weight percent boron oxide. The treated surface is inspected for surface flaws. Any discovered flaws are repaired by heating the surface to cause the borosilicate glass to flow and heal the flaw. The composite is thereafter heated to a further elevated temperature to deplete the boron from the flaw-sealing glass.
Inventors
- 👤 Robert L. Crane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:37
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B35/00; C04B35/71; C04B35/78; C04B35/80; C04B35/83; C04B41/45; C04B41/50; C04B41/5022; C04B41/52; C04B41/80; C04B41/81; C04B41/85; C04B41/86; C04B41/89; G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/91; G01N2021/8472
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
141 words
A method for detecting and repairing surface flaws in the silicon carbide oxidation resistant coating of a carbon-carbon composite which comprises the steps of: (a) providing a test liquid composition consisting essentially of a carrier fluid, at least one particulate pigment which is insoluble in said carrier fluid, finely divided silicon dioxide, and about 0.25 to 8 weight percent boron oxide, based upon the weight of the silicon dioxide; (b) applying said test liquid to the surface of said composite; (c) inspecting said surface for surface flaws; (d) heating said composite in at least the area of discovered surface flaws to an elevated temperature to fuse said boron oxide and said silicon oxide to form a coherent flaw-sealing coating in said surface flaws; and (e) thereafter heating said composite to a further elevated temperature to deplete boron from said flaw-sealing coating.
Claim 2
Independent Claim
141 words
A method for detecting and repairing surface flaws in the silicon carbide oxidation resistant coating of a carbon-carbon composite which comprises the steps of: (a) providing a test liquid composition consisting essentially of a carrier fluid, at least one particulate pigment which is insoluble in said carrier fluid, finely divided silicon dioxide, and about 0.25 to 8 weight percent boron oxide, based upon the weight of the silicon dioxide; (b) applying said test liquid to the surface of said composite; (c) inspecting said surface for surface flaws; (d) heating said composite in at least the area of discovered surface flaws to an elevated temperature to fuse said boron oxide and said silicon oxide to form a coherent flaw-sealing coating in said surface flaws; and (e) thereafter heating said composite to a further elevated temperature to deplete boron from said flaw-sealing coating.
Claim 3
Dependent Claim
41 words
The method of claim 1 wherein said test fluid composition consists essentially of about 0.1 to 5.0 volume percent of silicon dioxide, about 0.01 to 1.0 volume percent of pigment material and about 0.25 to 8 weight percent of boron oxide.
Claim 4
Dependent Claim
15 words
The method of claim 2 wherein said carrier fluid is a low molecular weight alcohol.
Claim 5
Dependent Claim
13 words
The method of claim 2 wherein said pigment material is a micro-encapsulated dye.
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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) | 1990-04-27 | 1990-10-27 | 1991-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-27 | 1994-10-27 | 1995-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-27 | 1998-10-27 | 1999-04-28 | $7700.00 | Window Closed / Lapsed |