Electrochemical study of growth behaviour of plasma electrolytic oxidation coating on Ti6Al4V: Effects of the additive

The growth behaviour of plasma electrolytic oxidation (PEO) coating on Ti6Al4V was studied by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization test, focusing on effects of the electrolyte additive – calcium hypophosphite. The EIS analysis of the outer layer of the PEO coating provided insight into the structure of the coating, which was confirmed by SEM results. The EIS analysis of the inner layer of the PEO coating provided information matching well with the results of the potentiodynamic polarization test.