Abstract: Titanium dioxide films containing Ca and P on titanium alloy were prepared by micro-arc oxidation. The effect of electrolyte composition and micro-arc voltage
on the phase construction, Ca/P atomic ratio, and morphology of the films were explored. The results show that the films are composed of anatase TiO₂ and
rutile TiO₂, which appear dense for inner layer and porous for outer layer in morphology. And Ca/P atomic ratios in the films tend to increase from the film/titanium
alloy interface to the surface. The content of amorphous TiO₂, size of pores, and Ca/P atomic ratio in the films are increased with increasing micro-arc voltage.
However, the films exhibit micro-cracks at higher micro-arc voltage. Increasing Ca/P ratio of the electrolyte can improve the Ca/P atomic ratio in the films.

Key words: micro-arc oxidation, titanium alloy, bio-film