Preparation And Mechanism Study Of Bioactive Oxide Film On The Surface Of Titanium Alloys

In this study, a novel electrochemical method for the preparation of bioactive titanium oxide films to improve the corrosion resistance and biocompatibility of the titanium alloys implant. Oxide films with different thickness and properties can be anodically formed on the surface of Ti6A14V alloy under different electrochemical conditions. The bonding strength of bonelike apatite layer formed on the titanium oxide films to the substrates under different heat treatment temperature is examined under tensile stress. Scanning electron microscopy (SEM), electron dispersive electron probe X-ray analyzer (EDX), Auger electron spectroscopy (AES) and the X-ray diffraction technique are used to characterize the structure and the chemical composition of the oxide films. The bioactivity of the anodized substrate is evaluated when it is subjected to alkali and heat treatment to form a sodium titanium hydrogel and bonelike apatite on the surface of titanium alloys in simulated body fuild (SBF) with ion concentrations nearly equal to those of human blood plasma.The results show that titanium oxide films prepared at room temperature consist of amorphous phase of titanium oxides, which can transform to crystal phase mainly consisting of anatase and rutile when they are subjected to appropriate heat treatment. Consequently the titanium oxide film with a high thickness can be considered an important improvement to solve the problem of metal ions release in the tissues surrounding the implant. The bonelike apatite is formed on the anodized substrate when it is subjected to alkali and heat treatment and then dip into the SBF solution. After 7 days the bond strength of bonelike apatite layer to the substrates can reach 36MPa.