Claims
- 1. A composite material, comprising:
- a copper or copper alloy substrate having first and second sides;
- a first anti-tarnish layer deposited on at least said first side, said first anti-tarnish layer being a nontransparent layer of co-deposited chromium and zinc having a zinc to chromium ratio in excess of about 13 to 1, by weight.
- 2. The composite material of claim 1 further including a second anti-tarnish layer adjacent said second side.
- 3. The composite coating of claim 2 wherein said second anti-tarnish layer is transparent.
- 4. The composite material of claim 3 wherein said second anti-tarnish layer has a zinc to chromium ratio of from about 5:1 to about 12:1.
- 5. The composite coating of claim 3 wherein said first side has a dendritic layer disposed between said copper or copper alloy substrate and said first coating layer.
- 6. The composite material of claim 5 wherein said first side has a zinc to chromium ratio of from about 13:1 to about 18:1.
- 7. An electrolytic process for applying a codeposited chromium and zinc anti-tarnish layer on at least one side of a copper or copper alloy substrate in an electrolytic cell having:
- first and second anodes in spaced relationship;
- an electrolyte containing an aqueous solution of hydroxide, zinc and chromium ions; and
- said copper or copper alloy substrate positioned between said first and second anodes and acting as the cathode;
- which process comprises impressing a first current density through said first anode and a second current density through said second anode and maintaining the temperature of said electrolyte to be effective to deposit a nontransparent anti-tarnish layer on said at least one side of said copper or copper alloy substrate.
- 8. The process of claim 7 wherein said electrolyte temperature is from about 50.degree. C. to about 90.degree. C.
- 9. The process of claim 8 wherein said electrolyte temperature is from about 60.degree. C. to about 80.degree. C.
- 10. An electrolytic process for applying a co-deposited chromium and zinc anti-tarnish layer on at least one side of a copper or copper alloy substrate in an electrolytic cell having:
- first and second anodes in spaced relationship;
- an electrolyte containing an aqueous solution of hydroxide, zinc and chromium ions; and
- said copper or copper alloy substrate positioned between said first and second anodes and acting as the cathode;
- which process comprises impressing a first current density through said first anode and a second current density through said second anode, said first current density being effective to deposit a nontransparent anti-tarnish layer on said at least one side of said copper or copper alloy substrate.
- 11. The process of claim 10 wherein said first current density is in excess of about 15 mA/cm.sup.2.
- 12. The process of claim 11 wherein said second current density is zero.
- 13. The process of claim 11 wherein said second current density is sufficiently low such that said second anti-tarnish layer is transparent.
- 14. The process of claim 13 including the step of forming a plurality of dendrites on the surface of said metallic substrate to be most proximate to said first anode prior to imparting said metallic substrate with an anti-tarnish coating.
- 15. The process of claim 14 wherein said second current density is from about 3 mA/cm.sup.2 to about 10 mA/cm.sup.2.
- 16. The process of claim 16 wherein said first current density is from about 30 mA/cm.sup.2 to about 50 mA/cm.sup.2.
- 17. A laminate comprising:
- a dielectric substrate;
- a copper or copper alloy foil having first and second sides, said first side laminated to said dielectric; and
- a nontransparent chromium-zinc layer deposited between said dielectric substrate and said copper or copper alloy foil.
- 18. The laminate of claim 17 wherein said chromium-zinc layer has a zinc to chromium ratio in excess of about 13:1.
- 19. The laminate of claim 17 wherein said zinc to chromium ratio is from about 13:1 to 18:1.
- 20. A laminate of claim 17 wherein said copper or copper alloy foil is patterned into a plurality of circuit traces.
CROSS-REFERENCED TO RELATED APPLICATION
This Application is a Continuation-in-Part of U.S. patent application Ser. No. 07/855,380, filed Mar. 20, 1992 which is a Continuation-in-Part of U.S. patent application Ser. No. 07/673,923 filed Mar. 25, 1991 which is now U.S. Pat. No. 5,098,796, which in turn is a Division of U.S. patent application Ser. No. 07/585,832, filed Sep. 20, 1990 which is now U.S. Pat. No. 5,022,968, which is a Continuation-in-Part of U.S. patent application Ser. No. 07/459,846 filed Jan. 2, 1990 (now abandoned) which in turn is a Continuation in Part of U.S. patent application Ser. No. 07/421,475 filed Oct. 13, 1989 (now abandoned).
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Divisions (1)
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585832 |
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Continuation in Parts (4)
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Date |
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855380 |
Mar 1992 |
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Parent |
673923 |
Mar 1991 |
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Parent |
459846 |
Jan 1990 |
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Parent |
421475 |
Oct 1989 |
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