The research progress of self-healing coatings for magnesium/magnesium alloy

Magnesium (Mg) and its alloys are promising candidates in both industrial and biomedical fields due to their excellent mechanical properties and biodegradability. However, their rapid corrosion severely hinders their widespread applications. Constructing coating is an effective method to prevent direct contact between corrosive ions and the Mg substrate. However, coatings are inevitably damaged in complex service environments, which compromises their corrosion protection ability. Therefore, it is essential to develop self-healing coating that can repair damage. This review focuses on recent advances in self-healing coatings for Mg alloy in both industrial and biomedical applications. Several types of self-healing coatings including conversion coating, encapsulation coating, layer-by-layer assembly coating, and external stimuli-responsive coating are reviewed, and their self-healing mechanisms are discussed, which discussions provides guidelines for designing self-healing coatings for Mg/Mg alloy.