Characteristics of high-performance anti-corrosion/anti-wear ceramic coatings on magnesium‑lithium alloy by plasma electrolytic oxidation surface engineering

Abstract High-performance anti-corrosion/anti-wear coatings on superlight magnesium‑lithium (Mg Li) alloy with exceptional durability are of great interest for fundamental research and practical applications. In the present study, oxide coatings are produced on Mg Li alloy by electrochemical surface engineering––plasma electrolytic oxidation in an alkaline silicate electrolyte with addition of cerium salt. To understand the nature of coatings, we investigate their surface and cross-sectional morphologies, wettability (35 ± 3° vs 78 ± 2°), phase and chemical compositions, corrosion and tribological behaviors. Our findings show that the oxide coating prepared with cerium salt has a more compact structure with fewer defects (18 μm in thickness). Importantly, it substantially enhances the corrosion resistance of Mg Li alloy by three orders of magnitude and significantly retards the occurrence of localized corrosion (150 h), along with notably improved anti-wear performance (friction coefficient of 0.19).