| Owing to its excellent mechanical properties and good biocompatibility, pure titanium is known as one of the ideal bone substitute materials. In order to modify the bioactivity of pure titanium and accelerate the rate of bone healing, micro-arc oxidation has been used to produce porous TiO2film on pure titanium, which contains Ca and P elements. The effect of process parameters on the organizational structure and performance of coatings were researched during the micro-arc oxidation. Besides, the mechanism of inducing apatite were analysed after post-treatments. The main results are as follows:The TiO2oxide film riching in Ca and P was obtained by the micro-arc oxidation. The thickness of the films were thickened with the increase of oxidized voltage. Anatase presented a dominant amount at lower voltage, rutile phase increased gradually with increase of voltage.The number of micropore in the surface of coatings decreased and the average micropore size increased with the increase of voltage and time. In addition, the surface roughness of micro-arc oxidized specimens was increased, the contact angles were decreased with the increase of applied voltage and oxidation time. But the excessive voltage and oxidation time resulted in cracking and shedding of the films.The bioactivity of micro-arc oxidized films containing Ca and P is poor. Alkali and heat treatment could have a better effect on the bioactivity of coating, and the pre-calcification treatment further improved the bioactivity of film and shortened the time to form apatite on the surface of samples significantly. The coating subjected to pre-calcification treatment displayed high apatite-inducing capability. The sodium titanate hydrogel layer formed during alkali treatment and the calcium titanate layer formed during pre-calcification treatment were the key factor to form apatite. At the same time, the improvement of post-treatments on the wetting ability could facilitate the growing of HA. |
PDF Full Text Request