Research on Thermal Spray Al-Al2O3/TiO2 Coating and Diffusion Treatment on Magnesium Alloy

Flame spray method was used to prepare the Al-Al2O3/TiO2 gradient coating on AZ91D magnesium alloy surface, where diffusion treatment for 2 hours at 380～420 °C was needed to reinforce the binding strength between the coating and the substrate. Appearance and compositions of the coating were analyzed by scanning electronic microscope (SEM) and electron probe microanalysis (EPMA), and the thermal shock resistance and wear resistance of the coating were tested. The result shows: Al-Mg diffusion is produced between the coating and the substrate, for good metallurgy; coating acquires high hardness and resistant to wear and thermal shock.