The Dissolution Mechanism of Iron in Chloride Solutions

We have measured the polarization curve and the electrochemical impedance for the dissolution of iron in sodium chloride solutions of varying pH of [, ] . The polarization curves are comparable with those of previous workers and exhibit two distinct Tafel slopes: 75 mV/s at low polarization, and 40 mV/decade at high polarization for . The impedance diagrams exhibit a high frequency capacitive loop, followed by one inductive loop at low overpotentials, and a further inductive loop at high overpotentials. We have interpreted these phenomena in terms of two parallel dissolution paths.