US3728155A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Copper alloy cleaning process
Assignee: Olin Corp
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Filing: 1971-06-18
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Granted: 1973-04-17
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Expires: 1991-06-18
Abstract
Abstract A process for removing surface oxides from copper alloys. For example, those alloys which form, on annealing, A12O3 and related oxides are uniquely cleaned by a process which consists of a duplex treatment requiring a first immersion in a hot alkaline solution followed by a second immersion in a hot mineral acid solution.
Inventors
- 👤 J Ford
- 👤 S Saunders
- 👤 E Caule
- 👤 Lain C Mc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:03
CPC Classifications
C; C23; C23G; C23G1/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
27 words
A process according to claim 1 in which sodium dichromate is present in the acid solution in an amount of from 1 to 8 ounces per gallon.
Claim 2
Dependent Claim
17 words
A process according to claim 1 in which the oxide is at least in part a spinel.
Claim 3
Dependent Claim
14 words
A process according to claim 1 in which said alkaline solution contains lithium hydroxide.
Claim 4
Dependent Claim
14 words
A process according to claim 1 in which said alkaline solution contains sodium hydroxide.
Claim 5
Dependent Claim
19 words
A process according to claim 1 in which the acid solution consists essentially of an aqueous solution of H2SO4.
Claim 6
Dependent Claim
20 words
A process according to claim 1 in which the thickness of the oxide after cleaning is less than 10 Angstrom.
Claim 7
Dependent Claim
18 words
A process according to claim 1 wherein the temperature of said alkaline solution is at the boiling point.
Claim 8
Dependent Claim
18 words
A process according to claim 1 in which the temperature of the acid is from 125*F to 175*F.
Claim 9
Dependent Claim
14 words
A process according to claim 9 wherein said pH is from 11 to 14.
References Cited (Backward Citations)
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Cited
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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) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |