As one of the lightest metallic structural materials, magnesium (Mg) alloys possess numerous distinctive properties and are utilized across a broad spectrum of applications. However, the poor corrosion resistance of Mg alloys limits their application. Micro-arc oxidation (MAO) is an effective surface treatment method that enhances the corrosion resistance of Mg alloys. Nevertheless, the intrinsic porous structure of MAO coatings hinders significant improvement in corrosion resistance. Research indicates that the pre- and post-treatment processes associated with MAO markedly enhance the densification of the oxide coatings, thereby improving their overall performance. This paper aims to provide a comprehensive review and analysis of the effects of various pre- and post-treatment processes, highlighting key advancements and research gaps in improving MAO coatings on Mg alloys. An in-depth analysis of the crucial role of pre-treatment in optimizing interfacial bonding and post-treatment in enhancing coating density is conducted using electrochemical testing and scanning electron microscopy (SEM). Finally, the future development of pre- and post-treatment processes are discussed.

Mg alloys, renowned for their lightweight and exceptional mechanical properties, hold promise for widespread applications in aerospace, automotive manufacturing, and biomedical fields. However, their limited corrosion resistance has hindered their practical usage. MAO (MAO) technology serves as an effective coating method to enhance the corrosion resistance of Mg alloys, yet the inherent porosity of MAO coatings remains a performance bottleneck. To optimize coating performance, pre-processing and post-processing have emerged as research hotspots. pre-processing regulates the surface state thereby promoting uniform growth of the MAO coating, while post-processing further reduces coating porosity and enhances corrosion resistance. This paper comprehensively reviews the impact of various pre-processing and post-processing methods, such as shot peening pre-processing and immersion post-processing, on the microstructure, composition, and performance of Mg alloy MAO coatings. Utilizing electrochemical testing and scanning electron microscopy (SEM) characterization techniques, the paper reveals the crucial role of pre-processing in optimizing interfacial bonding and post-processing in enhancing coating density.Finally, the paper concludes with a prospect on the development of pre-processing and post-processing techniques.