Surface protection of Mg alloys in automotive applications: A review

Mg alloys find widespread applications in transportation industries especially in cars and trucks because of their edges in light-weight design, which can greatly help improve the fuel efficiency and decrease the gas emissions of vehicles; However, Mg alloys’ high sensitivity to the corrosive environments limit their penetration in automotive applications. Surface coating is one of the most effective and economic ways to protect Mg alloys from corrosion. Presently, the currently researched and commercial coatings that are specifically applied to Mg alloys in the automotive industry are reviewed in this paper. With some Mg automotive components subjected to corrosion and repeated load simultaneously, corrosion fatigue of coated Mg alloys are reviewed as well. Additionally, a part of attention in this review is given to the assessment approaches of corrosion and corrosion fatigue performance of coated Mg alloys for the purpose of material/surface coating system selection. Finally, some corrosion-related challenges for the growth of Mg alloys, future developments and research directions on surface coatings and corrosion fatigue testing approaches are discussed.