A general model for the repassivation potential as a function of multiple aqueous solution species

A general model for predicting the localized corrosion repassivation potential of alloys in multicomponent electrolyte solutions is described. The model assumes that the status of localized corrosion is determined by competitive processes at the metal–salt film–solution interfaces leading to either metal salt or oxide formation. The model successfully predicts the observed effects of aggressive species, such as chloride and bromide, inhibiting species, such as nitrate, and non-aggressive species, such as acetate, for a number of Fe–Ni–Cr–Mo alloys. Furthermore, the model accurately predicts the effect of nitrate in a three-component system of chloride + nitrate + acetate, based only on parameters regressed for the constituent binary systems.