Electrochemical Impedance Spectroscopy of Aluminum Alloy Anode during Corrosion Process

The corrosion process of Al-Zn-In-Mg-Ti alloy in 3% NaCl solution was investigated with electrochemical impedance spectroscopy (EIS).The EIS was simulated using the equivalent circuit model.The EIS and surface corrosion morphology of the alloy showed that the pitting corrosion induced the alloy corrosion.The corrosion initiated from the passive film,and then the pitting corrosion from the inducement stage came to the stable stage.There was a big capacitive art of the reaction resistance Rt at high frequency at the passivation stage.At the inducement stage of pitting corrosion,there was an inductive art at the low frequency,while the solution resistance Rs increased,and the reaction resistance Rt and R0 in corrosion pit decreased and inductive L shriked.At the stable stage of pitting corrosion,the inductive art disappeared while a straight line appeared at the low frequency,the diffusion of corrosion product controlled the reaction process.