Corrosion degradation of AZ31 magnesium alloy coated by plasma electrolytic oxidation

Abstract Influence of plasma electrolytic oxidation (PEO) coating prepared using DC current technique on corrosion resistance of AZ31 magnesium alloy was studied. Morphology and chemical composition of the PEO coating was evaluated by scanning electron microscopy and EDS analysis respectively. Corrosion characteristics of ground and PEO coated samples were measured using electrochemical impedance spectroscopy (EIS) in 0.1 M NaCl. Scanning Kelvin Probe (SKP) technique was employed in order to investigate degradation mechanism of PEO samples after 24 h of salt spray test (NSS acc. to STN ISO 9227). Results showed that except of improved corrosion resistance of PEO coating, change of degradation mechanism was noticed after salt spray test.