Incorporation of MoO2 and ZrO2 particles into the oxide film formed on 7075 Al alloy via micro-arc oxidation

The influence of MoO2 and ZrO2 incorporations on the structure and corrosion properties of the oxide film of 7075 Al alloy coated by micro-arc oxidation was studied. For this purpose, micro-arc oxidation coatings were performed in a silicate-based electrolyte containing Na2MoO4 metallic salt and ZrO2 powder, and the results were compared to the counterpart without Na2MoO4 and ZrO2. From the electrochemical results of potentiodynamic polarization tests in 3.5 wt% NaCl solution, the sample treated in the electrolyte with Na2MoO4 and ZrO2 exhibited superior corrosion protection properties to that without Na2MoO4 and ZrO2 because the oxide films with small size of the micro-pores were controlled by the incorporations of MoO2 and ZrO2 particles.