US5098796A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chromium-zinc anti-tarnish coating on copper foil
Assignee: GBC Metals LLC
•
Filing: 1991-03-25
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Granted: 1992-03-24
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Expires: 2011-03-25
Abstract
Abstract A technique for improving the tarnish and oxidation resistance of copper and copper based alloy materials is disclosed. Copper or a copper alloy is immersed in an aqueous solution containing sodium hydroxide, zinc ions and chromium (VI) ions. While the compositional ranges may vary, the concentration of either zinc ions or chromium (VI) ions, or both, is less than 1.0 gm/1. A chromium-zinc coating is electrolytically applied. The coating provides tarnish resistance at temperatures in excess of 190 DEG C. The coating is removable by immerison in sulfuric acid. Improved results are obtained by rinsing deionized water containing a small amount of an alkaline or alkaline earth hydroxide.
Inventors
- 👤 Lifun Lin
- 👤 Chung-Yao Chao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:29
CPC Classifications
C; C25; C25D; C25D3/00; C25D3/02; C25D3/56; 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: 15
Claim 1
Independent Claim
40 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 co-deposited layer including zinc and chromium with a zinc-to-chromium ratio in excess of about 4:1.
Claim 2
Dependent Claim
40 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 co-deposited layer including zinc and chromium with a zinc-to-chromium ratio in excess of about 4:1.
Claim 3
Dependent Claim
17 words
A copper or copper based alloy material as in claim 1 wherein said coating layer is co-electrodeposited.
Claim 4
Dependent Claim
23 words
A copper or copper based alloy material as in claim 1 wherein said copper or copper based alloy material comprises a foil strip.
Claim 5
Dependent Claim
23 words
A copper or copper based alloy material as in claim 2 wherein said copper or copper based alloy material comprises a foil strip.
Claim 6
Dependent Claim
31 words
The copper or copper based alloy material of claim 3 wherein the thickness of said coating layer is effective to inhibit copper tarnish at temperatures of up to about 190° C.
Claim 7
Dependent Claim
26 words
The copper or copper based alloy material of claim 5 wherein the thickness of said coating layer is from about 10 angstroms to about 0.1 microns.
Claim 8
Dependent Claim
26 words
The copper or copper based alloy material of claim 6 wherein the thickness of said coating layer is from about 10 angstroms to about 100 angstroms.
Claim 9
Dependent Claim
23 words
The copper or copper based alloy material of claim 6 wherein said foil strip has at least one side roughened with dendritic copper.
Claim 10
Dependent Claim
21 words
The copper or copper based alloy material of claim 8 wherein said coating layer contains at least 20 atomic percent zinc.
Claim 11
Dependent Claim
21 words
The copper or copper based alloy material of claim 6 wherein said coating layer contains at least 20 atomic percent zinc.
Claim 12
Dependent Claim
93 words
The coated copper or copper based alloy material of claim 8 wherein said coating layer is deposited from a basic solution having hydroxide ions, from about 0.07 grams per liter to about 7 grams per liter zinc ions supplied in the form of a water soluble zinc compound and 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 ions or said chromium (VI) ions or both is less than 1.0.
Claim 13
Dependent Claim
29 words
The copper or copper based alloy material of claim 11 wherein said solution further includes lauryl sulfate in a concentration of from about 10 ppm to about 50 ppm.
Claim 14
Dependent Claim
93 words
The copper or copper based alloy material of claim 1 wherein said coating layer is deposited from a basic solution having hydroxide ions, from about 0.007 grams per liter to about 7 grams per liter zinc ions supplied in the form of a water soluble zinc compound and 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 15
Dependent Claim
29 words
The copper or copper based alloy material of claim 13 wherein said solution further contains lauryl sulfate in a concentration of from about 10 ppm to about 50 ppm.
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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) | 1995-03-24 | 1995-09-23 | 1996-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-24 | 1999-09-23 | 2000-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-24 | 2003-09-23 | 2004-03-24 | $7700.00 | Window Closed / Lapsed |