Influence alloying elements of Al and Y in Mg-Li alloy on the corrosion behavior and wear resistance of microarc oxidation coatings

Microarc oxidation (MAO) coatings were performed on different Mg-Li alloys (Mg-14Li, Mg-14Li-3Al, Mg-14Li-3Al-1Y) in silicate electrolyte. The morphology, thickness, corrosion behavior and wear resistance of the coatings were characterized and analyzed. Results indicate that, compared to Mg-14Li alloy, adding Al and Y in the substrate refines the grains and forms the AlLi and Al2Y phases, contributing to the differences in corrosion behaviors of the Mg-Li alloys. The alloying elements and uniformly fine microstructure modify the MAO growth process and promote the formation of thick coatings with fewer defects. The MAO coating on the Mg-14Li-3Al-1Y alloy possesses the best corrosion resistance with the icorr of 7.485 x 10(-6) A/cm(2), due to the densest coating and the thickest inner layer. The reduced porosity and smoother surface enhance the hardness and wear resistance of the MAO coatings on the Mg-14Li-3Al and Mg-14Li-3Al-1Y alloys. It is worth considering the refinement of microstructure and incorporation of passive elements for preparing compact MAO coatings with excellent per-formances on Mg-Li alloys.