METHOD OF ELECTROPLATING SILVER STRIKE OVER NICKEL

• US 20120067733A1
• Filed: 09/21/2011
• Published: 03/22/2012
• Est. Priority Date: 09/21/2010
• Status: Active Grant

• Current Assignee: Rohm and Haas Electronic Materials LLC (DuPont de Nemours, Inc.)
• Original Assignee: Rohm and Haas Electronic Materials LLC (DuPont de Nemours, Inc.)
• Inventors: ZHANG-BEGLINGER, Wan, SZÖCS, Edit, CLAUSS, Margit
• Granted Patent: US 9,228,268 B2
• Time in Patent Office: Days
• US Class Current: 205/170
• CPC Class Codes: C25D 3/46 of silver
• CPC Class Codes: C25D 3/50 of platinum group metals
• CPC Class Codes: C25D 5/10 Electroplating with more than one layer of the same or of different metals for bearings C25D7/10
• CPC Class Codes: C25D 5/12 at least one layer being of nickel or chromium
• CPC Class Codes: C25D 5/627 Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance

Abstract

A silver electroplating solution is used to electroplate a mirror bright silver layer on a nickel or nickel alloy substrate. The silver electroplating solution is cyanide-free and environmentally friendly.

Claims

1. A method comprising:

a) providing a solution comprising one or more sources of silver ions, one or more imides or imide derivatives and one or more alkali metal nitrates, the solution is cyanide-free;

b) contacting a substrate comprising nickel with the solution; and

c) electroplating a silver strike layer onto the nickel or nickel alloy.

2. The method of claim 1, further comprising a step of electroplating a second silver layer onto the silver strike layer.

3. The method of claim 1, wherein the silver strike layer is 0.01 μ

m to 0.2 μ

m thick.

4. The method of claim 1, wherein the second silver layer is 1 μ

m to 50 μ

m thick.

5. The method of claim 1, wherein the silver strike layer is electroplated at a current density of 0.1 A/dm² to 2 A/dm².

6. The method of claim 1, wherein the alkali metal nitrates are potassium nitrate and sodium nitrate.

7. The method of claim 1, wherein the imides are chosen from succinimide, 2,2-dimethyl succinimide, 2-methyl 2-ethyl succinimide, 2-methyl succinimde, 2-ethyl succinimde, 1,1,2,2-tetramethyl succinimide, 1,1,2-trimethyl succinimide, 2-butyl succinimide, maleimide, 1-methyl-2-ethyl maleimide, 2-butyl maleimide, 1-methyl-2-ethyl maleimide, pthalimide and pthalimide derivatives.

8. The method of claim 1, wherein the imide derivatives are chosen from hydantoin, 1-methylhydantoin, 1,3-dimethylhydantoin, 5,5-dimethylhydantoin, 1-methanol-5,5-dimethylhydantoin and 5,5-diphenylhydantoin.