Magnesium alloys are widely used in aerospace, automotive manufacturing, electronic equipment, and other fields due to their low density, high specific strength, and good casting properties. However, the poor corrosion resistance of magnesium alloys has greatly limited their further promotion and application. Therefore, how to improve the corrosion resistance of magnesium alloys has become one of the important topics in current materials science research.



The corrosion of magnesium alloys is mainly electrochemical corrosion, especially more obvious in humid environments or media containing chloride ions. Its corrosion mechanism is closely related to its low electrode potential, with the standard electrode potential of magnesium being -2.37 V (relative to the standard hydrogen electrode), which is the lowest among engineering metals. Therefore, it is easy to become an anode and undergo corrosion in most environments. In addition, impurity elements such as iron, nickel, and copper in magnesium alloys can also form microcells, accelerating the occurrence of localized corrosion.



To improve the corrosion resistance of magnesium alloys, it can be approached from multiple aspects such as material design, surface treatment, and protective coatings.



Firstly, in terms of alloy design, optimizing the composition of the alloy can significantly improve its corrosion resistance. For example, adding elements such as aluminum, zinc, and rare earth elements can form dense oxide films, enhancing the corrosion resistance of the alloy. In recent years, the development of AM series (such as AZ91D), AE series, and WE series magnesium alloys has made significant progress in corrosion resistance.



Secondly, surface treatment technology is an effective way to enhance the corrosion resistance of magnesium alloys. Common surface treatment methods include chemical conversion film, anodizing, micro-arc oxidation, and laser surface treatment. Among them, micro-arc oxidation treatment can generate a dense ceramic film on the surface of magnesium alloys, which has good corrosion and wear resistance and is widely used in industrial production.

　　Furthermore, painting and coating protection are also important means to improve the corrosion resistance of magnesium alloys. By methods such as electroplating, spraying, or applying organic coatings, an isolation layer can be formed on the surface of magnesium alloys to prevent the erosion of corrosive media. For example, epoxy resin coatings and polyurethane coatings can effectively block water and oxygen from contacting the matrix material.



In addition, the nanocomposite coating and self-healing coating technologies developed in recent years also provide new ideas for the corrosion prevention of magnesium alloys. These new materials not only have excellent physical barrier effects but can also self-repair external damage, thereby extending the service life of the material.



In summary, there are various methods to improve the corrosion resistance of magnesium alloys, and appropriate strategies should be selected according to specific application scenarios. With the continuous progress of materials science and technology, magnesium alloys are expected to achieve higher corrosion resistance while maintaining their lightweight and high-strength characteristics, providing more possibilities for future industrial development.