Electrodeposited White Bronzes: A Comparison between Zn-Bearing and Zn-Free Coatings

White bronzes are ternary alloys composed by Cu, Zn and Sn, named after their bright whitish colour. This class of alloys share excellent hardness, corrosion and tarnishing resistance, and is commonly adopted in galvanic industrial processes as technological grade coating, to obtain layers with particular aestethical and/or anticorrosive properties. Despite the widespread employment of white bronzes in fashion and electronics industry, recent literature lacks a characterization of these electrodeposited alloys in respect to more common binary (Cu-Sn) white bronzes.

In this presentation, a thorough characterization of a commercial ternary Cu-Zn-Sn white bronze, produced by electrodeposition, is reported. Structural, Chemical and Physical characteristics of the deposited coating were investigated by various techniques (e.g. FIB/SEM, XRF, XRD, EDX, microhardness, colour and corrosion tests). Results were compared with a similar set of measures obtained from a binary electrodeposited Cu-Sn white bronze (with a high tin content), in order to shed some light on the influence of Zn in the coating properties.