Influence of post-treatment process on corrosion and wear properties of PEO coatings on AM50 Mg alloy

Abstract In the present work, post-treatment process has been applied to improve the corrosion and wear resistance of plasma electrolytic oxidation (PEO) coated AM50 Mg alloy. The microstructure, chemical composition and corrosion resistance of the PEO/organic composite coatings were studied by means of SEM, FTIR, electrochemical corrosion test and salt spray test. The wear resistance of the coatings was investigated by performing dry sliding wear test. The results showed that sol-gel and epoxy layer were efficient to seal the open pores and therefore greatly enhanced the corrosion performance of PEO coatings, while hybrid coatings sealed by epoxy layer showed better corrosion and wear resistance. It was found that relatively long dipping time applied during post-treatment process is capable of fabricating denser coatings with superior coating properties. The open pores of the PEO coating are penetrated and filled effectively after performing post-treatment process, resulting in high adhesion force for the composite coatings.