Preparation and properties of hydroxyapatite-containing titania coating by micro-arc oxidation

A porous hydroxylapatite-containing titania film was prepared by a electrochemical oxidation method, i.e. micro-arc oxidation (MAO). During the oxidation treatment, the titanium sample was immersed in electrolytic solution containing calcium acetate monohydrate and sodium biphosphate dihydrate by using a pulse power supply. The thickness, phase, composition and morphology of the oxide coating were monitored with X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray spectrometer (EDS). The thickness of the MAO film was about 20 μm and the coating was porous and uneven, without apparent interface to the titanium substrates. The coating formed in the Ca- and P-containing solution with MAO contained Ca and P along with Ti and O. The Ca / P ratio on the surface is 1.63, while that in the interface is 0.51. XRD showed that the porous coating was made up of anatase, rutile and hydroxyapatite. Such MAO films are expected to have significant medical applications as dental implants and artificial bone joints.