THE EFFECTS OF ZINC ALLOY ELECTROPLATING ON THE HYDROGEN EMBRITTLEMENT OF HIGH-STRENGTH STEELS

The electrodeposition of a metallic coating on to high strength steel introduces the possibility that the steel will fail by hydrogen embrit tlement. This paper describes a fundamental study of the hydrogen upta ke resulting from electroplating with zinc-nickel alloys in a mildly a cidic sulphate bath. Hydrogen permeation measurements were performed a nd indicated that the quantity of hydrogen absorbed by the steel subst rates is critically dependent on the composition of the initial deposi t. Large quantities of hydrogen were trapped in the coatings and conti nued to diffuse into the steel over extended times after the plating p rocess was completed.