Studies on the Electrodeposition of Ternary Copper-Zinc-Tin Alloys

Abstract

SummaryThe colour of Cu-Zn-Sn alloy coatings obtained by electrodeposition may differ-white, gold, dark gold, pink, and so on—depending on the specific combination of deposition conditions such as electrolyte composition, temperature, pH value and current density. Effects of pH and current density on the colour of the deposits and the associated electrode processes at the cathode and anode during deposition have been investigated. It was found that increasing either pH or current density causes an increase in the Zn content of the deposit and results in a colour trend away from pink and towards yellow. It was also found that cathodic deposition takes place in the sequence Sn, Cu, Zn, followed by Cu-Zn-Sn alloy. Anodic dissolution occurs at—1.0 V. From this study a reproducible gold-coloured coating was achieved, which could be of considerable practical importance.