Abstract: In order to improve the biocompatibility of NiTi alloy, TiO₂ films were synthesized on the surface by sol-gel and Ion beam enhanced deposition (IBED) methods, respectively.
The structure, surface morphology and composition of the films were studied comparatively by X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray
photoelectron spectra (XPS). The electrochemical corrosion measurement showsthat the two kinds of TiO2 films both can improve the corrosion resistance
of metallic biomaterials in simulated body fluid as a protective layer on the surface. In order to further improve the anticoagulation of implants, immobilization
of heparin molecule on the film surface was also investigated. The results indicate that sol-gel-derived TiO₂ film can obtain better heparin immobilization effects
than Ion beam derived TiO₂ film.

Key words: sol-gel, IBED, TiO2 film, heparin immobilization