Patent US3615950A successfully refreshed from Google Patents.
US3615950A
Expired / Lapsed
US
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Method of etching silver-tin-lead contacts on a nickel coated base
Assignee: US Philips Corp
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Filing: 1969-04-15
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Granted: 1971-10-26
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Expires: 1989-04-15
Abstract
Abstract A method of chemically etching away lead-tin-silver alloy layers from a base in which the body is dipped in a solution of ammonia and an ammonium salt and then etched in a solution of hydrogen peroxide and an acid.
Inventors
- 👤 Rodolphe Lacal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 08:34
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/44; C23F1/10; C23F1/14; C23F1/16; C23F1/30; H; H10; H10P; H10P95/00
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
30 words
The method of claim 1 wherein the mixture contains equal volumes of the ammonium bicarbonate solution and the ammonia solution and the time is for about 5 to 10 minutes.
Claim 2
Dependent Claim
19 words
The method of claim 1 wherein the etching bath contains in addition a buffer and a surface active substance.
Claim 3
Dependent Claim
15 words
The method of claim 3 wherein the surface active substance is a sulfonated lauryl alcohol.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |