Abstract:Micro-arc oxidation coatings on biomedical titanium alloys were fabricated in an aqueous solution of Na2SiO3 at different impulse frequency. The morphology, phase composition, wear resistance and corrosion resistance of the MAO coating were studied by scanning electron microscope (SEM), X-ray diffractometry, CETR UMT Multi-Specimen Test System and IVIUM Electrochemical Workstation. The results show that the MAO coating has a large number of micropores and it is mainly composed of anatase and rutile TiO2. Within the experimental impulse frequency range, the porosity of the MAO coatings increases first, and then decreases with the frequency increasing; however, the average pore size decreases first, and then increases. The thickness of coatings decreases with the rising of frequency. When the frequency is kept at 700 Hz, the surface morphology is smooth and micropores of the MAO coating are distributed homogenously, the porosity reaches the maximum value 11.04%, and the average pore size reaches the minimum value 0.86 μm; meanwhile the best wear and corrosion resistance is obtained.