Influence of surface pre-treatment on the deposition and corrosion properties of hydrophobic coatings on a magnesium alloy

Calcium stearate based hydrophobic coatings were deposited on pre-treated Mg alloy substrates. The influence of four different pre-treatments including plasma electrolytic oxidation (as prepared and etched), anodizing and hydrothermal treatment was studied. The results indicate that the pre-treatments have strong influences on the morphology, thickness, and wettability of the coatings, without affecting their phase composition. The coating system based on the etched plasma electrolytic oxidation pre-treatment shows the best corrosion resistance in a simulated body fluid. The superior protection effect is mainly related to the differences in the morphologies and thickness of the pre-treatment layers.