Effects of Graphene Oxide on the Mechanical and Tribological Properties of Micro-Arc Oxidation Coatings on Aluminum Alloy

Abstract

In order to improve wear resistance of aluminum alloy，the aluminum alloy was treated by micro-arc oxidation (MAO) in the hexametaphosphate composite electrolyte with adding different contents of graphene oxide (GO) nanoparticles.Scanning electron microscopy(SEM)，X-ray diffractometer (XRD)，film thickness gauge and microhardness tester were used to analyze the effects of GO on the micromorphology，phase composition，element distribution，thickness and microhardness of micro-arc oxide coatings.Furthermore，the friction and wear properties of aluminum alloy micro-arc oxide coatings under different GO concentrations were studied.Results showed that the addition of GO nanoparticles in the electrolyte had a significant effect on the micro-arc oxide coating.The growth rate of Al2O3/GO coatings increased with the increase of GO content，and the main components were α-Al2O3 and γ-Al2O3.With the increase of GO concentration，the microhardness of the micro-arc oxidation coating was significantly improved compared with that of pure 2A12 aluminum alloy.Owing to the incorporation of C elements into the coating interface during the electrolytic oxidation process，the surface of the Al2O3/GO coating became dense and smooth，the friction coefficient was significantly reduced and the wear resistance was raised.In general，this method could provide a new idea for strengthening surface wear resistance of aluminum alloy and has great significance for expanding the application of aluminum alloys.

Keywords

• aluminum alloy|micro-arc oxidation|graphene oxide|mechanical properties|tribological properties