Influence of KF Concentration on Thickness and Energy Consumption of Micro-Arc Oxidation Coatings on LY12 Aluminum Alloy Substrate

In this paper, ceramic coatings were produced on LY12 aluminum alloy by the micro-arc oxidation (MAO) technique in an alkali sodium silicate electrolyte consisting of different KF concentrations(0~15g/l). The influence of KF concentration on making energy consumption and thickness of the MAO coatings was studied. Results revealed that increasing KF concentration caused an increase in the thickness and roughness of coatings and a decrease in the average energy during the MAO process. In response to the increase in KF concentration, the little content of F- in the coatings were increased simultaneously. However, the phase structure and composition of the coatings hardly varied with different KF concentrations. Moreover, it was observed that the coatings produced in electrolytic solution with 10g/L concentration of KF obtained an excellent thickness and making energy, but the coatings were ablated locally with the KF concentration of higher than 10g/L for more than 60 minutes.