Preparation of TiO2 film containing phosphorus on biomedical NiTi alloy by sol-gel method

TiO2 thin films containing phosphorus were prepared by the sol-gel method in order to further improve the biocompatibility of NiTi surgical alloy. Atomic force microscopy (AFM) analyses indicate that the surface of the films packed with micrometer-sized particles is uniform and smooth. The corrosion behaviors of NiTi alloy with the surface coated with the film and non-treated samples were investigated in the Tyrode' biological solution by the anodic polarization curves measurement. The results indicate that the corrosion resistance of NiTi alloy is improved due to the protective film on the surface. In vitro the bioactivity in simulated body fluid (SBF) was tested and the surface composition was analyzed by XPS. The results show that the films can induce Ca and P deposition on the surface. It is therefore suggested that the sol-gel-derived TiO2 films containing P can be used to improve the corrosion resistance and the bioactivity of NiTi alloy.