In order to solve the problem of poor electrical conductivity of conventional magnesium alloy MAO coatings and to further enhance the multifunctionality of magnesium alloy coatings, this study examines the enhancement of EW75 through the development of composite coatings designed to improve its corrosion resistance, electrical conductivity, hydrophobicity, and antibacterial properties. MAO was employed as a base treatment, followed by application of organic composite coatings containing conductive graphite powder, silver-copper alloy powder, or a combination of both. Coatings were comprehensively characterized to evaluate their microstructure, corrosion resistance, electrical conductivity, hydrophobicity, and mold resistance. Results indicated that composite coatings significantly enhanced corrosion resistance compared to pure MAO coatings, with MAO-AgCu composite coating exhibiting the best performance. Furthermore, coatings demonstrated improved electrical conductivity, with MAO-AgCu coating displaying the lowest surface resistivity. Hydrophobicity was significantly improved in MAO–C-AgCu coating, and all coatings exhibited robust antibacterial effects, particularly against mold growth. This study enhances magnesium alloys’ functionality, with potential applications in corrosion protection, electrical properties, and antimicrobial resistance.

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.

The microstructure and precipitated phases of as-cast Mg-5Y-1.5Nd-xZn-0.5Zr (x = 0, 2, 4, 6 wt.%) alloys were investigated by optical microscopy, scanning electron microscopy, energy-dispersive spectrometry and X-ray Diffraction. The exposure corrosion experiment of these magnesium alloys was tested in South China Sea and KEXUE vessel atmospheric environment. The corrosion characteristic and mechanism of magnesium alloys of Mg-5Y-1.5Nd-xZn-0.5Zr (x = 0, 2, 4, 6 wt.%) alloys were analyzed by weight loss rate, corrosion depth, corrosion products and corrosion morphologies. The electrochemical corrosion tests were also measured in the natural seawater. The comprehensive results showed that Mg-5Y-1.5Nd-4Zn-0.5Zr magnesium alloy existed the best corrosion resistance whether in the marine atmospheric environment and natural seawater environment. That depended on the microstructure, type and distribution of precipitated phases in Mg-5Y-1.5Nd-4Zn-0.5Zr magnesium alloy. Sufficient quantity anodic precipitated phases in the microstructure of Mg-5Y-1.5Nd-4Zn-0.5Zr alloy played the key role in the corrosion resistance.