This paper analyses the formation process of ceramic coating formed by microarc oxidation and describes the phenomenon of microzone are discharge in surface of sample.The phase structure and morphology of ceramic coating on LY12 aluminum alloy are investigated by XRD and SEM.The results show that ceramic coating of microarc oxidation on alunimum alloys mainly contains α- Al2O3,γ-Al2O3 phases. Microarc takes part in the formation of ceramic phases. Ceramic coating is composed of the two-layer structure with ...