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 consisted of metallic zinc and nickel and zinc dissolution products, showing a three-layers Ž < .Ž. structure. In the first layer the film electrolyte interface zinc was always present as Zn OH with some adsorbed water.2 The second layer was a transition region where the content of metallic zinc increased and that of oxygen decreased until a constant composition was reached. The third layer was located in the bulk film and it was mainly composed of a-phase Zn–Ni alloy doped with zinc hydroxide or simonkolleite, depending on the time.