Formation of CaTiO3/TiO2 composite coating on titanium alloy for biomedical applications

Plasma electrochemical oxidation (PEO) was used to prepare TiO2-based coating containing Ca and P on titanium alloy. After alkali- and then heat-treatment at 800 degrees C of the PEO coating, a CaTiO3/TiO2 composite (CTC) coating was obtained. The current results indicate that the apatite-forming ability of the CTC coating is higher than that of the PEO coating. During the simulated body fluid (SBF) incubation, Ca of the CTC coating is released into the SBF. An ionic exchange between Ca2+ ions of the CTC coating and H3O+ ions of the SBF may take place during the SBF incubation. As a result, the abundant Ti-OH groups are formed on the surface of the CTC coating. The hydroxyl functionalized surface greatly enhances the nucleation and growth of apatite, leading to the high apatite-forming ability of the CTC coating. The apatite induced by the CTC coating exhibits a porous and carbonated structure. (C) 2007 Wiley Periodicals, Inc.