Abstract:Micro-arc oxidation (MAO) films on pure titanium were prepared in sodium tungsten electrolyte and in potassium dihydrogen phosphate electrolyte, respectively. The surface and cross-section morphologies, the element distribution and the phase composition of coatings were analyzed by means of SEM, EDX, XRD. The photocatalytic activity of the two coatings was tested by UV-Vis spectra. The results show that MAO coatings prepared in the two electrolytes are rough and micro-porous, but the pores on the surface of the coating prepared in the sodium tungsten electrolyte are smaller and more homogeneous. The composition and the phase constitution of the coatings depent on the electrolyte composition, The coating prepared in the sodium tungstate solution mainly consists of elements W, Ti, O, element W is distributed homogeneously in the coating, and the ratio of anatase to rutile is 27:73, while the elements of the coating prepared in the potassium dihydrogen phosphate electrolyte are P, Ti, O, the content of P gradually increased from the surface to the dense layer, and the ratio of anatase to rutile is 84:16. The result of absorbance test shows that the photocatalytic activity of the coating formed in sodium tungsten electrolyte is higher than that of the coating formed in the potassium dihydrogen phosphate electrolyte, because of its larger specific surface area