Abstract: Effect of adding different concentration of Ti nanoparticles in silicate electrolyte on the morphology, structure and corrosion resistance of AZ91D magnesium alloy micro-arc oxidation film were studied by SEM, EDS, electrochemical workstation and hydrogen evolution test. The results show that with the addition of 0.25-1.00 g/L Ti nanoparticles, the number of micropores decreases, the film thickness increases, the compactness increases, and the corrosion resistance firstly increases and then decreases with the increase of concentration of Ti nanoparticles. In the process of micro-arc oxidation, TiO₂ is generated to fill some holes in the micro-arc oxidation film and improve the quality of the film. When the concentration of Ti nanoparticles is 0.50 g/L, the corrosion resistance of the Ti micro-arc oxide film can be increased by more than 3 orders of magnitude in 0.6 mol/L sodium chloride solution, and the hydrogen evolution rate can be reduced greatly.

Key words: AZ91D Mg alloy, micro-arc oxidation, corrosion resistance, titanium nanoparticles