Corrosion mechanisms of iron in concentrated acidic zinc chloride media

Abstract A mechanism for the anodic dissolution of iron in concentrated zinc chloride media is proposed as an ECE mechanism. The rate determining step is the formation of a Fe-Cl reaction intermediate. This mechanism was found to be suitable for interpretation of kinetic electrochemical parameters obtained in these solutions. Radiotracer studies showed that the iron interface is saturated with Cl − at low concentrations which is responsible for the change in the iron dissolution mechanism. The phenomenon of the region of non-polarizability is interpreted in terms of the electrochemical desorption of the Cl − ion at high dissolution rates. The hydrogen evolution reaction was found to be inhibited due to the underpotential deposition of zinc. The effect of decreasing water activity in solutions of high ionic strength is found to significantly decrease i o,Fe , i o,H - and i corr values.