Electroplating solutions

Patent metadata

Field	Value
Publication number	US-2023407507-A1
Application number	US-202118250487-A
Country	US
Kind code	A1
Filing date	Dec 16, 2021
Priority date	Dec 18, 2020
Publication date	Dec 21, 2023
Grant date	—

Abstract

The invention relates to an aqueous electroplating solution for alkaline electroplating, comprising: [M(NH3)4]2+ ions, wherein M is selected from the group consisting of Pd or Pt; and organic anions selected from the group consisting of bicarbonate, carbonate, or a mixture thereof; wherein the following species, if present, are present in the following amounts: alkali metals in an amount of less than 5 g/L; compounds comprising phosphorus in an amount of less than 5 g/L; compounds comprising boron in an amount of less than 5 g/L. The invention also relates to an electroplating bath comprising the electroplating solution, and a method of forming a metal layer on a substrate by electroplating using the electroplating solution.

First claim

1 . An aqueous electroplating solution for alkaline electroplating, comprising:
[Pt(NH 3 ) 4 ] 2+ ions; and organic anions selected from the group consisting of bicarbonate, carbonate, or a mixture thereof; wherein the molar ratio of Pt:(bicarbonate+carbonate) is from 1:1 to 1:10; and wherein the following species, if present, are present in the following amounts: alkali metals in an amount of less than 5 g/L; compounds comprising phosphorus in an amount of less than 5 g/L; compounds comprising boron in an amount of less than 5 g/L.

2 . (canceled)

3 . The aqueous electroplating solution according to claim 1 , wherein the molar ratio of Pt:(bicarbonate+carbonate) is from 1:1 to 1:5.

4 . The aqueous electroplating solution according to claim 1 , wherein the molar ratio of Pt:(bicarbonate+carbonate) is approximately 1:2.

5 . The aqueous electroplating solution according to claim 1 , wherein the molar ratio of Pt:(bicarbonate+carbonate) is approximately 1:1.

6 . (canceled)

7 . The aqueous electroplating solution according to claim 1 , wherein the concentration of Pt in the solution is 1 to 30 g/litre, on a metal basis.

8 . The aqueous electroplating solution according to claim 1 , wherein the pH of the solution is 8 to 14.

9 . The aqueous electroplating solution according to claim 1 , comprising a pH adjusting agent selected from the group consisting of ammonia, urea, an alkylammonium hydroxide, ammonium hydroxide, ammonium bicarbonate and ammonium carbonate.

10 . The aqueous electroplating solution according to claim 1 , wherein the content of alkali metals is less than 0.1 g/L.

11 . The aqueous electroplating solution according to claim 1 , wherein the content of halide ions in the electroplating solution is less than 1 g/L.

12 . The aqueous electroplating solution according to claim 1 , wherein the content of nitrite ions in the electroplating solution is less than 0.5 g/L.

13 . The aqueous electroplating solution according to claim 1 , wherein the content of nitrate ions in the electroplating solution is less than 0.5 g/L.

14 . The aqueous electroplating solution according to claim 1 , wherein the content of compounds containing silicon is less than 0.5 g/L.

15 . The aqueous electroplating solution according to claim 1 , wherein the content of compounds containing sulfur is less than 0.5 g/L.

16 . An electroplating bath comprising a cathode and an anode which are both at least partially submerged in an electrolyte, wherein the electrolyte is the aqueous electroplating solution according to claim 1 .

17 . A method of forming a metal layer on a substrate by electroplating, wherein electroplating is carried out using a bath comprising a cathode and an anode which are both at least partially submerged in an electrolyte, wherein the electrolyte is the aqueous electroplating solution according to claim 1 .

18 . The method as claimed in claim 17 , wherein electroplating is carried out at a temperature of 80° C. or more.

19 . The method as claimed in claim 17 , wherein electroplating is carried out at a temperature of 60 to 100° C. or more and a pH of 8 to 14.

20 . The method as claimed in claim 17 , wherein the bath is replenished with fresh electroplating solution as required.

21 . The method as claimed in claim 17 , wherein a pH adjusting agent is added to the bath as required.

22 . The method as claimed in claim 17 , wherein the cathode provides the substrate to be coated.

23 . The method as claimed in claim 17 , comprising a step of pausing electroplating and increasing the temperature of the electrolyte in order to purge the bath of residual organic anion.

24 . The method as claimed in claim 17 , wherein the cathode acts as the substrate and is selected from jewellery, a medical component or an aviation component.

Assignees

• Johnson Matthey Plc

Inventors

• Boardman Alan

Classifications

• C25D3/52 Primary

  characterised by the organic bath constituents used · CPC title

• C25D3/50 Primary

  of platinum group metals · CPC title

• C25D7/005

  Jewels; Clockworks; Coins · CPC title