Mechanism of anodic dissolution and passivation of iron - I. Behavior in neutral acetate buffer solutions

The kinetics of the anodic dissolution and passivation of Fe have been studied in neutral and slightly acidic acetic acid/sodium acetate buffer solution as a function of the total acetate buffer concentration and pH. The results have been obtained from potential sweep experiments at 5 mV s-1, which corresponds to quasi-steady state conditions. Two anodic peaks were found in the active dossulition region of the voltammogram. (...) Galvanostatic cathodic reduction experiments were used to characterize the surface film formed during the anodic sweep. A mechanism is proposed which accounts for the observed reaction orders, and simulates the observed anodic voltammograms in a semi-quantitative fashion. The mechanism provided a simple, physical explanation for the observed negative reaction order with respoect to acetate concentration.Peer reviewed: YesNRC publication: Ye