Electrochemical impedance spectroscopic investigation of dissolution, passivation and pitting corrosion of tin in Na2CO3 solution and the effect of Cl− and I− ions

Electrochemical impedance spectroscopy (EIS) was used to study the dissolution, passivation and pitting corrosion of tin in aqueous solution of Na2CO3 in absence and presence of Cl− and I− ions. Two simplified equivalent circuits were fitted to the experimental impedance data. The proposed model describes the main features of the characteristic behavior of the electrode process including the formation of passive and active pits. EIS was used to obtain electrolyte resistance, pore resistance, polarization resistance and fractal dimensions of tin electrode in the above-examined solutions. The data indicate that the corrosion rate and the pitting corrosion were increased by the addition of halide ions.