US4339282A
Expired / Lapsed
US
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Method and composition for removing aluminide coatings from nickel superalloys
Assignee: RTX Corp
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Filing: 1981-06-03
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Granted: 1982-07-13
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Expires: 2001-06-03
Abstract
Abstract Nickel aluminide and like coatings are stripped from nickel base superalloy substrates using a 60°-71° C. solution consisting essentially by volume percent of 43-48 nitric acid, 7-12 hydrochloric acid, balance water, and containing 0.008-0.025 mole/liter ferric chloride and at least 0.016 mole/liter copper sulfate. Coating removal is rapid while significant attack of the substrate is avoided.
Inventors
- 👤 Henry Lada
- 👤 Robert E. Fishter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:47
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/44
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
51 words
The process of removing an aluminide coating from a nickel superalloy article characterized by contacting the coating with a stripping solution having a composition consisting essentially by volume percent of 43-48 concentrated nitric acid, 7-12 concentrated hydrochloric acid, 40-50 water, at least 0.016 mole/liter CuSO 4 and 0.008-0.025 mole/liter ferric chloride.
Claim 2
Dependent Claim
51 words
The process of removing an aluminide coating from a nickel superalloy article characterized by contacting the coating with a stripping solution having a composition consisting essentially by volume percent of 43-48 concentrated nitric acid, 7-12 concentrated hydrochloric acid, 40-50 water, at least 0.016 mole/liter CuSO 4 and 0.008-0.025 mole/liter ferric chloride.
Claim 3
Dependent Claim
40 words
The process of claim 1 wherein the composition is more particularly characterized as 43-48 concentrated nitric acid and 9-11 concentrated hydrochloric acid, 41-48 water, and wherein the molar ratio of FeCl 3 and CuSO 4 is maintained at about 1:2.
Claim 4
Dependent Claim
33 words
The process of claims 1 or 2 wherein the solution is maintained at about 60°-71° C. and wherein the article is removed from contact with the solution and vapor blasted at periodic intervals.
Claim 5
Dependent Claim
39 words
A stripping solution for removing an aluminide coating from a nickel base superalloy consisting essentially by volume percent of 43-48 concentrated nitric acid, 7-12 concentrated hydrochloric acid, 40-50 water, at least 0.016 mole/literCuSO 4 and 0.008-0.025 mole/liter ferric chloride.
Claim 6
Dependent Claim
39 words
A stripping solution for removing an aluminide coating from a nickel base superalloy consisting essentially by volume percent of 43-48 concentrated nitric acid, 7-12 concentrated hydrochloric acid, 40-50 water, at least 0.016 mole/literCuSO 4 and 0.008-0.025 mole/liter ferric chloride.
Claim 7
Dependent Claim
36 words
The stripping solution of claim 4 more particularly characterized as 43-48 concentrated nitric acid, 9-11 concentrated hydrochloric acid, 41-48 water, and wherein the molar ratio of FeCl 3 and CuSO 4 is maintained at about 1:2.
References Cited (Backward Citations)
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Cited
US3467599A
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US3859149A
Cited
US3856694A
Cited
US4032359A
Cited
US4089736A
Cited
US4274908A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-12 | 1986-01-11 | 1986-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-12 | 1990-01-11 | 1990-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-12 | 1994-01-11 | 1994-07-13 | $7700.00 | Window Closed / Lapsed |