Acidic aqueous silver-nickel alloy electroplating compositions and methods

Patent metadata

Field	Value
Publication number	US-11242609-B2
Application number	US-201916653216-A
Country	US
Kind code	B2
Filing date	Oct 15, 2019
Priority date	Oct 15, 2019
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

Silver-nickel alloy electroplating compositions and methods enable electroplating silver rich silver-nickel deposits which are bright, uniform and have a relatively low coefficient of friction. The binary silver-nickel alloy is deposited from an aqueous acid silver-nickel alloy electroplating composition. The aqueous acid silver-nickel alloy electroplating composition includes thiol compounds which shift the reduction potential of silver ions toward the reduction potential of nickel ions such that a silver rich binary silver-nickel layer is deposited on a substrate.

First claim

What is claimed is:

1. A silver-nickel alloy electroplating composition composed of water, silver ions and counter anions, nickel ions and counter anions, a thiol compound selected from the group consisting of 2-mercaptosuccinic acid, 3-mercapto-1-propanesulfonic acid, 1-[2-(dimethylamino)ethyl]-1H-tetrazole-5-thiol, salts thereof and mixtures thereof, optionally a dihydroxy bis-sulfide compound, optionally a thiocarbonyl compound, optionally a metallic brightening agent, optionally an acid or salt thereof, optionally a pH adjusting agent, optionally a surfactant and optionally a biocide, wherein a pH is less than 7.

2. The silver-nickel alloy electroplating composition of claim 1 , wherein the pH is from 0 to 6.5.

3. The silver-nickel alloy electroplating composition of claim 1 , wherein the thiol compound is in amounts of 5 g/L or greater.

4. The silver-nickel alloy electroplating composition of claim 3 , wherein the thiol compound is in amounts of 10-100 g/L.

5. The silver-nickel alloy electroplating composition of claim 4 , wherein the thiol compound is in amounts of 15-90 g/L.

6. A method of electroplating nickel metal on a substrate comprising:
a) providing the substrate;
b) contacting the substrate with a silver-nickel alloy electroplating composition composed of water, silver ions and counter anions, nickel ions and counter anions, a thiol compound selected from the group consisting of 2-mercaptosuccinic acid, 3-mercapto-1-propanesulfonic acid, 1-[2-(dimethylamino)ethyl]-1H-tetrazole-5-thiol, salts thereof and mixtures thereof, optionally a dihydroxy bis-sulfide compound, optionally a thiocarbonyl compound, optionally a metallic brightening agent, optionally an acid or salt thereof, optionally a pH adjusting agent, optionally a surfactant and optionally a biocide, wherein a pH is less than 7; and
c) applying an electric current to the silver-nickel alloy electroplating composition and substrate to electroplate a silver-nickel deposit on the substrate.

7. The method of claim 6 , wherein the silver-nickel alloy electroplating composition has a pH of 0 to 6.5.

Assignees

• Rohm & Haas Elect Mat
• Rohm And Hass Electronic Mat Llc

Inventors

• Chen Jamie Y C
• Lipschutz Michael
• Rodriguez Miguel A
• Lo Kin Cheung

Classifications

• C25D7/005

  Jewels; Clockworks; Coins · CPC title

• C25D7/00

  Electroplating characterised by the article coated · CPC title

• C25D3/64 Primary

  containing more than 50% by weight of silver · CPC title