Microstructure and properties of rare earth CeO${}_2$-doped graphene composite coatings prepared by MAO on AA7050

In this paper, ceramic coatings were prepared on the surface of 7 050 high strength aluminum alloy using a micro-arc oxidation process in a silicate electrolyte combined with the rare earth element cerium or graphene. To analyze the surface morphology, roughness, phase composition, and corrosion resistance, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectrometry, and electrochemical measurements were used, respectively. It was shown that the micro-pore size of the composite coatings, which mainly consisted of α-Al${}_2$O${}_3$ and γ-Al${}_2$O${}_3$, decreases and the density improved with the simultaneous addition of 4 g · L${}^{-1}$ of CeO${}_2$ and 10 g · L${}^{-1}$ of graphene to the electrolyte. In addition, with the addition of CeO${}_2$ and graphene, the roughness was the lowest and the corrosion resistance was significantly improved.