Research on Composite Sealing Process and Performance of Micro - Arc Oxidation Film on AZ80 Magnesium Alloy

Characterization methods such as scanning electron microscopy (SEM), X - ray diffractometer, electrochemical test, and friction and wear test were used to study the effects of different sealing treatments on the microstructure and properties of AZ80 magnesium alloy ceramic films which have already treated by micro - arc oxidation (MAO). Results showed that after the NaOH pretreatment and polymethyl trime thoxy silane (PMTMS) / polytetra fluoroe thylene (PTFE) composite sealing treatment, the MAO films could obtain the optimal hole - sealing effect on the surface. In addition, the roughness of MAO films decreased, while the abrasion resistance was improved. After the composite sealing treatment, the corrosion potential (Ecorr) of the film layer moved positively from -0.45 V of the MAO film to -0.12 V, and the corrosion current density (Jcorr) of the film layer dropped from 1.79×10-5 A/cm2 of the MAO film to 4.51×10-6 A/cm2, indicating that the corrosion performance was significantly improved.