Formation process of micro arc oxidation coatings obtained in a sodium phytate containing solution with and without CaCO 3 on binary Mg-1.0Ca alloy

•Compared to the Mg phase, the area of Mg2Ca phase is much smaller.•The coatings are preferentially developed on the area adjacent to Mg2Ca phase.•During MAO process, some sodium phytate molecules are hydrolyzed.•Anodic coatings are developed from uneven to uniform.