Corrosion and Anti-Corrosion Mechanisms of Epoxy Resin/Graphene and Epoxy Resin/Graphene Oxide Composite Coatings on Magnesium Alloys

Graphene and graphene oxide are potential anti-corrosion materials. In this study, epoxy resin/graphene and epoxy resin/graphene oxide composite coatings were succeed prepared. Hydrogen evolution and electrochemical experiments were conducted to determine key parameters—including hydrogen evolution rate, hydrogen evolution volume, corrosion current density, and corrosion potential—of the designed composites in a 3.5 wt.% NaCl solution. The sample with the highest graphene oxide content was 0.8295 μA/cm2, representing a two-order-of-magnitude decrease compared to the matrix. Combined with scanning electron microscopy, the surface morphologies of various coatings after corrosion were observed, and the corrosion mechanisms of magnesium alloys with these coatings were carefully discussed. Based on electrochemical analysis, this study proposes and verifies that the working mechanism of the composite coatings relies on a physical barrier rather than a redox reaction.