Surface analysis of films formed on a zinc anode in a Zn-Ni electroplatingbath

The films obtained on a zinc anode in a zinc-nickel electrolyte under open circuit conditions were characterized by XRD, SEM and XPS. The film consist ed of metallic zinc and nickel and zinc dissolution products, showing a thr ee-layers structure. In the first layer (the film\electrolyte interface) zi nc was always present as Zn(OH)(2) with some adsorbed water. The second lay er was a transition region where the content of metallic zinc increased and that of oxygen decreased until a constant composition was reached. The thi rd layer was located in the bulk film and it was mainly composed of alpha-p hase Zn-Ni alloy doped with zinc hydroxide or simonkolleite, depending on t he time. (C) 1999 Elsevier Science B.V. All rights reserved.