The anodic dissolution of zinc RDE and passive film formation were studied in NH4Cl+ NICl2 and NH4Cl+ NiCl2 + ZnCl2 electrolytes at pH 5.5. A passivation process of the Zn electrode was observed in these Ni-containing solutions, which was a result of cathodic reactions of the Ni and/or Zn-Ni alloy electrodeposition and zn(OH)(2) precipitation. XPS data indicated that the outer part of the film (the film/electrolyte interface) was almost exclusively zinc hydroxide, while the bulk film was a metallic matrix with constant composition (cr-Zn-Ni alloy) and it incorporated zinc oxidation products. These results indicated that the composition of the film obtained under anodic polarization or in open circuit conditions was not the same. The zinc dissolution reaction in Ni-containing electrolytes was determined by a diffusion stage; at high rotation speeds the Zn dissolution reaction became controlled by the slow removal of zinc-oxygen containing, which were formed both at the open circuit potential and at anodic polarization and also by the diffusion of the dissolution products within pores.