A dense ceramic oxide coating approximately 45 µm thick was prepared on a Ly12 aluminum alloy by micro-arc oxidation in an alkali-phosphate electrolytic solution. Coating thickness and surface roughness (Ra) were measured after the coating had been synthesized. The effects of Al2O3 Nanoparticles in electrolyte on phase composition, microstructure and microhardness of the micro-arc oxidation ceramic coatings on Ly12 aluminum alloy were investigated by means of XRD, SEM and hardness experimentation. The results show that the ceramic coatings become more dense and its microhardness increased by adding Al2O3 Nanoparticles in electrolyte. In addition, the roughness of the micro-arc oxidation ceramic coatings is obviously improved by addition of Al2O3 Nanoparticles.
