In this research work, the influence of thermal oxidation treatment on corrosion behavior, bioactivity and improving of surface characteristics of titanium has been investigated. Thermal oxidation treatments were carried out at 400- 800 ?C by a heating rate of 5 ?C / min in a conventional muffle furnace under air atmosphere for 1 h followed by cooling in the furnace. The chemical treatment of samples was performed before thermal oxidation process. For this purpose, some samples were completely dipped in acidic solution for a few minutes. Others were soaked in 5M NaOH solutions at 60°C for 10 h. Corrosion resistance (Tofel curves) and bioactivity were investigated in simulated body fluid. For the evaluation of surface characteristics of oxidized samples, instruments such as SEM equipped with EDS, XRD, optical microscopy observation, hardness test, TGA, GDOS and adhesion tests using a scotch tape were used. It is proposed that thermal oxidation process can induce an adherent oxide layer, supported by an oxygen diffusion zone beneath it. With increasing oxidation temperature, the hardness parameter of surface was increased. The treatment can also improve corrosion resistance for both types of chemical treatments. The effect of oxidation processing on bioactivity of samples, which were dipped in NaOH solution, is higher than other specimens. The maximum corrosion resistance and bioactivity were obtained at 600°C. It is concluded that thermal oxidation of titanium can be successfully done in air. This treatment can greatly influence both corrosion resistant and bioactivity behaviour.
