Patent ID: 11905613
Assignee: COVENTYA S.P.A.
Field: Surface technology, coating (Chemistry)
Classification: CPC C | IPC C

Claim 20:
21. An electroplating bath for depositing chromium metal coating on a substrate or chromium metal alloy coating on a substrate consisting of:
(a) 50 to 400 g/L (0.164 M to 1.314 M) of at least one trivalent chromium salt,
(b) 100 to 400 g/L (2.17 M to 8.68 M) of at least one complexing agent,
(c) 5 to 50 g/L (0.0425 M to 0.425 M) of at least one halogen salt, and
(d) 0.5 to 10 g/L of additives, wherein the additives comprise a quaternary ammonium compound, and
(e) 70 to 110 g/L of ammonia,
wherein the electroplating bath has a pH from 4 to 7;
wherein the molar ratio of the complexing agent to the trivalent chromium salt is from 10:1 to 15:1,
wherein the at least one complexing agent is selected from the group consisting of carboxylic acids and carboxylate salts,
whereby, when the substrate is immersed in the electroplating bath and an electrical current is applied, the substrate is deposited with a chromium metal coating or a chromium metal alloy coating.