The passivation of zinc in acids or concentrated salt solutions leads to a passivating, non-porous salt film. Anodic voltammetric curves under potentiodynamic conditions are characterized by a common current density peak, which is followed by a lower but relatively pronounced corrosion current density which is constant up to 90 V. A quantitative interpretation of the current Voltage curve is possible if a mixed electrode kinetics is employed. The charge transfer kinetics is due to the ZnZn2+ electrode. Transport kinetics is related to the diffusion-migration of anions through the thin passivating salt film toward the metal. In the early stages of potentiodynamic polarization, the salt film is established according to a dissolution-precipitation mechanism. The thickness of this film governs the rate of transport of anions through the film. In the steady state, the corrosion current density j(c) is constant. The dissolution rate of the salt equals the anodic rate of generation of the salt. Experimental curves (Zn/1 M H2SO4) agree excellently with the theoretical curves produced by this model. The mathematical procedure is described in detail.