PEO-coating/substrate interface investigation by localised electrochemical impedance spectroscopy

The features of the corrosion process in the artificial defect on the coating obtained by plasma electrolytic oxidation (PEO) method on an MA8 magnesium alloy were investigated using the localised electrochemical impedance spectroscopy (LEIS) technique. The analysis of the experimental data enabled us to suggest that the corrosion process in the defect zone develops predominantly at the magnesium/coating interface. The LEIS technique allows detecting the precision alterations result from corrosion process, which can not be found by optical image.