Evaluation of corrosion behaviour of Pb-Co3O4 electrodeposited coating using EIS method

Pb-Co3O4 composite coating was electrodeposited using direct and pulsed current on Pb-Ca-Sn substrate. Corrosion evaluation using electrochemical impedance spectroscopy (EIS) in copper electrowinning electrolyte revealed that PC deposited coating has higher corrosion resistance than its DC counterpart, due to its higher incorporated particles and increased surface homogeneity. However, it was demonstrated that the presence of CoSO4 as an additive in the electrolyte is crucial for the coating (irrespective of the deposition method) to maintain its higher electrochemical stability. Moreover, after prolonged polarization, the coating exhibited higher impedance in the subsequent EIS results as compared to that of the substrate.