Graphene-based coatings for magnesium alloys: exploring the correlation between coating architecture, deposition methods, corrosion resistance and materials selection

Abstract

Abstract Graphene and its derivatives have attracted much interest as corrosion-resistant coatings for magnesium alloys since 2014, when the first reports appeared in the literature. The interest in the use of such carbonaceous compounds to protect magnesium and its alloys from corrosion relies on a set of attributes such as chemical inertness, and high surface area. To support the development of optimized graphene-based films it is imperative to expand the current knowledge toward a deeper understanding of corrosion mechanisms and their interaction with practical aspects related to coating deposition and morphology. In the present work, graphene-based coatings for magnesium alloys are reviewed. We explored the correlation between coating architecture, deposition methods and materials selection using the Ashby approach. The results of the materials selection process revealed that composite coatings consisting of an inorganic matrix obtained by plasma electrolytic oxidation of magnesium alloys and graphene oxide nanosheets as blocking agents can provide surfaces with high corrosion resistance in sodium chloride solution. For biomedical applications, composite coatings consisting of a mixture of organic matrices such as chitosan and graphene oxide as reinforcing particles are attractive candidates. The results are discussed based on coating architecture and its interplay with the corrosion properties.