US5230932A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chromium-zinc anti-tarnish coating for copper foil
Assignee: GBC Metals LLC
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Filing: 1992-03-20
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Granted: 1993-07-27
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Expires: 2012-03-20
Abstract
Abstract A technique for improving the tarnish and oxidation resistance of copper and copper based ally material is disclosed. The material is electrolytically coated by immersion in an aqueous electrolyte containing sodium hydroxide, zinc ions and chromium (VI) ions. The deposited coating is a codeposited layer of zinc and chromium with a zinc to chromium ratio of from about 5:1 to about 12:1. The coating provides tarnish resistance at temperatures in excess of 190 DEG C. and is removable by immersion in sulfuric acid.
Inventors
- 👤 Szuchain F. Chen
- 👤 Nina Yukov
- 👤 Lifun Lin
- 👤 Chung-Yao Chao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:06
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/38; H05K3/382; H05K3/384; H05K2201/00; H05K2201/03; H05K2201/0332; H05K2201/0335; H05K2201/0355; H05K2203/00; H05K2203/07; H05K2203/0703; H05K2203/0723; H05K3/22; H05K3/24; H05K3/244; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9335; Y10S428/934; Y10S428/935; Y10T; Y10T428/00; Y10T428/12; Y10T428/12431; Y10T428/12438; Y10T428/12493; Y10T428/12771; Y10T428/12785; Y10T428/12792; Y10T428/12861; Y10T428/12903
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
44 words
A copper or copper based alloy material having a coating layer to improve resistance to tarnishing at elevated temperatures wherein said coating layer comprises a codeposited layer including zinc and chromium with a zinc to chromium ratio of from about 5:1 to about 12:1.
Claim 2
Dependent Claim
44 words
A copper or copper based alloy material having a coating layer to improve resistance to tarnishing at elevated temperatures wherein said coating layer comprises a codeposited layer including zinc and chromium with a zinc to chromium ratio of from about 5:1 to about 12:1.
Claim 3
Dependent Claim
23 words
The copper or copper based alloy material of claim 1 wherein said zinc to chromium ratio is from about 6:1 to about 10:1.
Claim 4
Dependent Claim
94 words
The copper or copper based alloy material of claim 1 wherein said codeposited layer including chromium and zinc is electrolytically deposited from an electrolyte containing from about 0.07 grams per liter to about 10 grams per liter zinc ions supplied in the form of a water soluble zinc compound, from about 0.1 grams per liter to about 100 grams per liter of chromium (VI) ions in the form of a water soluble hexavalent chromium salt wherein the concentration of either said zinc ions or said chromium (VI) ions or both is less than 1.0.
Claim 5
Dependent Claim
16 words
The copper or copper based alloy material of claim 3 wherein said material comprises foil strip.
Claim 6
Dependent Claim
16 words
The copper or copper based alloy material of claim 3 wherein said material comprises a leadframe.
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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) | 1996-07-26 | 1997-01-25 | 1997-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-26 | 2001-01-25 | 2001-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-26 | 2005-01-25 | 2005-07-27 | $7700.00 | Window Closed / Lapsed |