Comprehensive study on corrosion, wear and fatigue performance of low-porosity PEO coating on Mg alloy

• Novel neutral electrolyte was designed to reduce the high porosity of PEO coatings. • Presence of additive tunes the microstructure and phase composition of the coating. • The dense coating remains uncorroded after performing salt spray test for 1 month. • Corrosion fatigue limit was improved for the optimized coating. • The coatings survived after exposure 1 year in South China Sea environment. Novel neutral electrolytes were designed to substantially decrease porosity and increase barrier property of plasma electrolytic oxidation (PEO) coating on AM50 Mg surface. Presence of additives was effective in tuning coating microstructure and composition, leading to significantly enhanced corrosion and wear properties. 50% improvement in fatigue limit was detected for the optimized coating compared to conventional PEO coating. The low-porosity coating remained uncorroded after performing salt spray test for 1 month, and exposure 1 year in harsh South China Sea environment. This can be new strategy to evaluate coating lifespan and promote wide range of applications for Mg alloy.