Characterization of graphene oxide/ZrO2 composite coatings deposited on zirconium alloy by micro-arc oxidation

Abstract

ZrO2 coatings combined with graphene oxide (GO) was prepared on N36 zirconium (Zr) alloy by micro-arc oxidation (MAO) technique. MAO coating shows a typical volcano-like structures with pores and cracks. The MAO coating with GO is composed with m-ZrO2 and t-ZrO2. The electrochemical test indicates that MAO coating provides good corrosion protection to Zr alloy, and corrosion resistance enhance significant with GO concentration increasing. The increasing in corrosion resistance is mainly due to that GO particles in the coating act as a barrier to the diffusion pathway of electrolyte and restrain aggressive electrolyte accessing to the substrate. Fretting wear test indicate that MAO coating with GO exhibits a lower coefficient of friction (COF) and wear volume compared with that of Zr alloy substrate and MAO coating without GO. Optimal concentration of GO in MAO coating is 0.05 g/L. Low COF and wear volume is attributed to the lubrication function of GO particle, and the lubrication of GO particle is caused by low shear stress of different GO layer. Wear mechanism of MAO coating with GO is mainly adhesive wear. Good corrosion and wear resistance prompt the MAO coating of Zr alloy becoming accident tolerant candidate cladding material used for reactor in nuclear power plant.