Patent US4614673A successfully refreshed from Google Patents.
US4614673A
Expired / Lapsed
US
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Method for forming a ceramic coating
Assignee: Boeing Co
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Filing: 1985-06-21
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Granted: 1986-09-30
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Expires: 2005-06-21
Abstract
Abstract A gelled film can be deposited directly on a sensitive substrate to obtain a protective ceramic coating on the substrate. An alumina sol, for example, can be sprayed through a flowing stream of ammonia to create a uniformly thick film, which adheres to metals, plastics, or, in some cases, water soluble materials. This film can then be cured, usually at low firing temperatures, to complete the coating.
Inventors
- 👤 Anna L. Bendig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:18
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/02; C23C18/12; C23C18/125; C23C18/1254; C23C18/1204; C23C18/1208; C23C18/1225; C23C18/1279
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
97 words
A method for forming a protective ceramic coating on the surface of a sensitive substrate, such as on a metal, a metal matrix composite, or a plastic which is not wet by a conventional sol, the method comprising the steps of: (a) spraying a sol, containing a ceramic precursor in a carrier through a flowing stream of a suitable gas to alter the pH of the sol, and, thereby, to deposit a gelled film directly on the surface; and (b) drying and curing the film under conditions suitable for the substrate to complete the protective ceramic coating.
Claim 2
Independent Claim
97 words
A method for forming a protective ceramic coating on the surface of a sensitive substrate, such as on a metal, a metal matrix composite, or a plastic which is not wet by a conventional sol, the method comprising the steps of: (a) spraying a sol, containing a ceramic precursor in a carrier through a flowing stream of a suitable gas to alter the pH of the sol, and, thereby, to deposit a gelled film directly on the surface; and (b) drying and curing the film under conditions suitable for the substrate to complete the protective ceramic coating.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein the sol is made from aluminum alkoxide (Al(OR) 3 ).
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein step b occurs at a temperature below about 600° F.
Claim 5
Dependent Claim
10 words
The method of claim 1 wherein the gas includes ammonia.
Claim 6
Dependent Claim
23 words
The method of claim 1 further comprising the steps of repeating steps a and b to build up the coating in successive layers.
Claim 7
Dependent Claim
10 words
The method of claim 1 wherein the carrier includes water.
Claim 8
Dependent Claim
11 words
The method of claim 1 wherein the carrier includes an alcohol.
Claim 9
Dependent Claim
22 words
The method of claim 2 wherein the sol includes a sufficient amount of a suitable acid to hydrolyze and peptize the alkoxide.
Claim 10
Independent Claim
104 words
A method for forming a protective alumina coating on the surface of a sensitive substrate, such as on a metal, a metal matrix composite or a plastic which is not wet by a conventional alumina sol, the method comprising the steps of: (a) spraying an alumina sol containing alumina in isopropanol at the surface through a flowing stream of anhydrous ammonia to deposit a gelled film directly on the surface; (b) continuing the spraying to build up a substantially uniform film of the desired thickness; and (c) drying and curing the film at a temperature between 200°-600° F. to complete the protective alumina coating.
Claim 11
Independent Claim
104 words
A method for forming a protective alumina coating on the surface of a sensitive substrate, such as on a metal, a metal matrix composite or a plastic which is not wet by a conventional alumina sol, the method comprising the steps of: (a) spraying an alumina sol containing alumina in isopropanol at the surface through a flowing stream of anhydrous ammonia to deposit a gelled film directly on the surface; (b) continuing the spraying to build up a substantially uniform film of the desired thickness; and (c) drying and curing the film at a temperature between 200°-600° F. to complete the protective alumina coating.
Claim 12
Independent Claim
135 words
A method for forming a protective, transparent, alumina coating on the surface of a sensitive substrate, such as on a metal or plastic which is not wet by a conventional alumina sol the method comprising: (a) preparing a hydrolyzed sol by adding aluminum alkoxide to a carrier of water, isopropanol, or a mixture thereof; (b) peptizing the hydrolyzed sol to form a clear sol by adding a sufficient amount of a suitable acid to the sol, such that the ratio of acid/hydroxide is at least about 0.03 on a molar basis; (c) spraying the peptized sol through a flowing stream of ammonia at the surface of the substrate to deposit a gelled film on the surface; and (d) drying and curing the film at a temperature below about 600° F. to complete the protective coating.
Claim 13
Independent Claim
135 words
A method for forming a protective, transparent, alumina coating on the surface of a sensitive substrate, such as on a metal or plastic which is not wet by a conventional alumina sol the method comprising: (a) preparing a hydrolyzed sol by adding aluminum alkoxide to a carrier of water, isopropanol, or a mixture thereof; (b) peptizing the hydrolyzed sol to form a clear sol by adding a sufficient amount of a suitable acid to the sol, such that the ratio of acid/hydroxide is at least about 0.03 on a molar basis; (c) spraying the peptized sol through a flowing stream of ammonia at the surface of the substrate to deposit a gelled film on the surface; and (d) drying and curing the film at a temperature below about 600° F. to complete the protective coating.
Claim 14
Dependent Claim
25 words
The method of claim 10 wherein the sol is prepared with vigorous stirring, and the hydrolysis step occurs at a temperature of about 170° F.
Claim 15
Dependent Claim
36 words
The method of claim 11 wherein the acid is selected from the group consisting of nitric, hydrochloric, perchloric, acetic, and trichloroacetic acids and wherein the ratio of acid/hydroxide is between about 0.03-0.10 on a molar basis.
Claim 16
Dependent Claim
10 words
The method of claim 12 wherein the carrier is water.
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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) | 1989-09-29 | 1990-03-31 | 1990-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-29 | 1994-03-31 | 1994-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-29 | 1998-03-31 | 1998-09-30 | $7700.00 | Window Closed / Lapsed |