Factors Influencing the Heat Wastage Efficiency and Density of Micro-arc Oxidation

The coatings of magnesium alloy were prepared by microarc oxidation at different current densities(3, 6, 9, 12 and 15 A/dm2) in silicate solution. The influences of current density on the temperature variation of solution, heat wastage efficiency and compactness of film were investigated. The results show that with increasing the current density, the temperature variation increased from 18 ℃ to 33 ℃, the heat wastage efficiency decreased at first stage and then increased, the compactness of film increased first and then decreased.