Characterization of Micro-Arc Oxidation Coating on Surface of ZAlSi12Cu2Mg1 Alloy in the Electrolyte Containing Li2CO3

\ A varying content of Li2CO3 was added into Na2SiO3+NaOH system base electrolyte. The micro-arc oxidation ceramic coatings were prepared on the surface of ZAlSi12Cu2Mg1 alloy in the electrolytes and the coatings were characterized by vortex thickness gauge, XRD, SEM and EDS in this work. The results show that the thickness of oxide film increases from 71 mu m to 126 mu m with increasing of the content of Li2CO3 from 4.0 to 6.0 g/L. The reverse current decreases with increasing of the oxidation time in the MAO process, and the rate of current decrease accelerates with increasing of the content of Li2CO3. It is found by SEM that the roughness of film decrease and then rise, but the size of microspore increase on the surfaces of the film. It is found by XRD that the oxide films were mainly composed of Mullite and Al2O3. The results of EDS analysis indicate that the distribution of chemical elements of the film surface are mainly O, Al and Si, as well as a trace amount of Na and Mg.