Preparation and characterisation of CaP-containing coating on magnesium alloy by micro-arc oxidation and hydrothermal treatment

摘要

Micro-arc oxidation (MAO) together with hydrothermal treatment had been performed to improve the corrosion resistance of magnesium alloy. The oxide films were hydrothermally heated at 150°C for 2h. The morphology of samples were characterized by SEM/EDS. The phase compositions were examined by TF-XRD. The corrosion resistance of the coatings was evaluated by electrochemical methods in Hank's solution. The MAO films displayed porous and rough structure and were mainly composed of MgO and MgAl_2O_4 After hydrothermal treatment, a dicalcium phosphate dihydrate (DCPD) coating formed on the oxide film. The corrosion resistance of the MAO film and DCPD coating was increased by about 12 and 40 times higher than that of bare magnesium alloy.