Effect of annealing on the wear performance of MAO coatings

The Ti6Al4V alloy was first subjected to annealing treatments at different temperatures to obtain various microstructures, followed by micro-arc oxidation (MAO) treatment. This study investigated the influence of annealing treatment on the microstructure and wear behaviour of MAO coatings. The results indicate that annealing treatment affects the microstructure of MAO coatings, potentially due to variations in electrical conductivity of the substrate. A higher electrical conductivity enhances the growth of MAO coatings, leading to an increase in their thickness and a higher rutile TiO ₂ content. The primary wear mechanism of MAO coatings is adhesive wear. Meanwhile, high hardness and low porosity collectively enhance their wear resistance. Notably, the MAO coatings prepared on the alloy annealed at 860 °C exhibit low roughness, low porosity, high hardness, and the lowest wear rate of 79.65 μm³·N ⁻ ¹·m ⁻ ¹.