Corrosion-Resistant Electrochemical Platings on Magnesium Alloys: A State-of-the-Art Review

Industrial deployment of magnesium alloys in most instances requires anti-corrosion coatings. Distinct from conversion coatings, the electro/electroless plating techniques are emerging as the common means of coating magnesium; however, more research is needed. A state-of-the-art review was undertaken with respect to aqueous plating systems (including pretreatment, under-coating, and electroplating), electroless plating (being treated individually, though it is used as undercoating for subsequent plating in some cases), non-aqueous plating systems (including high-temperature molten salts and ionic liquids), and novel plating methods. In addition to the performance assessment of various plated coatings on magnesium alloys, merits and demerits of existing plating techniques are discussed. Based on the literature to date, the practical issues faced in magnesium plating are raised, and possible advances discussed, providing some instructive guidelines for future work.