Patent US3607398A successfully refreshed from Google Patents.
US3607398A
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Chemical stripping process
Assignee: Avco Corp
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Filing: 1969-06-18
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Granted: 1971-09-21
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Expires: 1989-06-18
Abstract
Abstract Aluminide coatings are removed without attack of the substrate by immersion of coated articles in an aqueous liquid composed of a mixture of orthophosphoric acid, nitric acid and acetic and/or chloroacetic acid. For more rapid chemical stripping, the mixture of acids should be heated.
Inventors
- 👤 Joseph G Lucas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:45
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/44
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
18 words
The process of claim 1 wherein at least some of the acetic acid is replaced by chloroacetic acid.
Claim 2
Dependent Claim
26 words
The process of claim 1 wherein the immersion is in heated mixture of acids, heated to a temperature between about 130* F. and about 220 F.
Claim 3
Dependent Claim
47 words
The process of claim 1 wherein the mixture of acids is heated to between about 140* and 165* F. before an article to be stripped is immersed therein and then heated to between about 185* and 200 F. after the part is immersed and the stripping proceeds.
Claim 4
Dependent Claim
22 words
The process of claim 1 wherein the stripped substrate is permitted to cool in the solution until no further action is visible.
Claim 5
Dependent Claim
23 words
The process of claim 1 wherein, after completion of stripping, the substrate is removed from the stripping mixture and is then liquid honed.
Claim 6
Dependent Claim
16 words
The process of claim 1 wherein the coating removed is nickel aluminide deposited by flame spraying.
Claim 7
Dependent Claim
17 words
The process of claim 1 where in the coating removed is nickel aluminide deposited by pack cementation.
Claim 8
Dependent Claim
16 words
The process of claim 1 wherein the coating removed is an aluminide formed by any means.
Claim 9
Dependent Claim
42 words
The process of claim 1 wherein the relative proportions of acids in the stripping mixtures are respectively 2:1:1 by volume, based on a phosphoric acid concentration of 85 percent, nitric acid concentration of 70 percent, and acetic acid concentration of 99 percent.
Claim 10
Dependent Claim
12 words
The process of claim 10 wherein the temperature is about 165* F.
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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) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |