Corrosion Resistance of Decorative Platings Deposited from Cobalt Citrates

Studies on Improvement in Corrosion Resistance of Decorative Platings from Cobalt Baths with Insoluble Anode (Part 6)

Abstract

CASS and corrodkote tests on a decorative plating containing an intermediate cobalt layer from citrates were conducted to examine its high corrosion resistance processes.
Following conclusions were drawn:
(1) Corrosion surroundings had effects on the formation of small blisters.
(2) The electrode potential between each two plating layers had effects on the formation of small blisters under definite surroundings.
(3) The undercoating of cobalt layer should be electrochemically nobler than the bright nickel.
(4) The preferred processes for high corrosion resistance of decorative platings were as follows:
Cu……Co……bright Ni……regular Cr
Cu……semi-bright Ni……Co……bright Ni……regular Cr and their modifications.