US4425185A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and composition for removing nickel aluminide coatings from nickel superalloys
Assignee: RTX Corp
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Filing: 1982-03-18
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Granted: 1984-01-10
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Expires: 2002-03-18
Abstract
Abstract Disclosed is a method for stripping nickel aluminide coatings of up 10 weight percent aluminum from nickel base alloy substrates at room temperature. The preferred solution contains by volume percent 43-45 nitric acid, 7-12 hydrochloric acid, 0.1-1.5 sulfuric acid, balance water; it also contains 0.008-0.025 moles per liter of ferric chloride, at least 0.016 moles per liter copper sulfate. The ratio between the sulfate and chloride is 2:1 or greater.
Inventors
- 👤 Robert E. Fishter
- 👤 Henry Lada
- 👤 Victoria M. Putnam
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:09
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/44
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
54 words
The method of removing a nickel aluminide coating from a wrought non-hardenable nickel base alloy characterized by contacting the article with an acid solution consisting essentially by volume percent of 43-45 concentrated nitric acid, 7-12 concentrated hydrochloric acid, 0.1-1.5 concentrated sulfuric acid, balance water; the solution also containing metal chloride and metal sulfate ions.
Claim 2
Independent Claim
54 words
The method of removing a nickel aluminide coating from a wrought non-hardenable nickel base alloy characterized by contacting the article with an acid solution consisting essentially by volume percent of 43-45 concentrated nitric acid, 7-12 concentrated hydrochloric acid, 0.1-1.5 concentrated sulfuric acid, balance water; the solution also containing metal chloride and metal sulfate ions.
Claim 3
Dependent Claim
40 words
The method of claim 1 characterized by a solution containing 0.008-0.025 moles per liter ferric chloride and at least 0.016 moles per liter copper sulfate, wherein the ratio between copper sulfate and ferric chloride is maintained at 2:1 or greater.
Claim 4
Dependent Claim
21 words
The method of claim 1 wherein the article is periodically removed from the acid solution and subjected to wet abrasive cleaning.
Claim 5
Independent Claim
20 words
The method of claims 1 or 2 wherein the temperature of the acid solution is in the range 20°-60° C.
References Cited (Backward Citations)
US4032359A
Cited
US4274908A
Cited
US4325756A
Cited
US4302246A
Cited
US4353780A
Cited
US4339282A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-09 | 1987-07-11 | 1988-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-09 | 1991-07-11 | 1992-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-09 | 1995-07-11 | 1996-01-10 | $7700.00 | Window Closed / Lapsed |