Influence of graphene on corrosion properties of micro arc oxidation coatings on 7075 aluminum alloy

Abstract

AbstractThis study uses 7075 aluminum alloy as the base material and employs micro arc oxidation technology to prepare ceramic coatings with different concentrations of graphene particles on the surface of the 7075 aluminum alloy. The effects of graphene particle concentration on micro arc oxidation behavior and coating performance were investigated through X‐ray diffraction, scanning electron microscope, electrochemical testing, and other performance characterization methods. The research results show that the addition of graphene particles helps to promote the transformation of metastable γ‐Al2O3 to stable α‐Al2O3, thereby enhancing the corrosion properties of the coating. When the concentration of graphene particles is 3 g/L, the prepared micro arc oxidation coating has the maximum thickness and hardness, which are 17.13 µm and 886.76 HV0.3, respectively, while the porosity and roughness are the smallest, which are .39 µm and 4.79%, respectively. Electrochemical test results show that the self‐corrosion current density is the smallest at this concentration, which is 2.323 × 10−9A/cm2. Therefore, the addition of graphene particles can effectively improve the corrosion properties of 7075 aluminum alloy.