The effect of Anodic oxidation on oxide film of pure titanium

Objectives: To study the oxide film of pure titanium implant material treated by anodic oxidation. Methods: Five commercially pure (CP) titanium sheets (9mm in diameter and 2mm thick) were treated by the speed of 7~8 v/min of potential, the current density <= 10mA/cm2 to (A) 10v for10min, (B) 24v for 10min, (C) 40v for 10min, (D) 24v for 40min, (E) 24v for 2hr in Kawahara's electrochemical solution. Four sheets of CP titanium were ground and treated with anodic oxidation at 24v10min. The electro-chemical behavior of anodic oxide film and natural oxide film was studied using a potentiostat. Results: The color of samples changed from white to the following: A¨Cblue, B-light gold, C-pink, D-media gold, E-dark gold. Along with the potential and time going on, the peak 2.55 strengthened, and peak 2.34 weakened. The voltage-time curve in physiological salt solution (PSS) showed that the open circuit potential (OCP) of the anodic oxide was very stable at 0mV. Natural oxide increased quickly beginning from ¨C50~-40mV and plateaued 350s later at ¨C40mV. The curve of anodic polarization in the same liquid showed that the polarized current was 100 times lower than that of natural oxide film. Conclusion: The color of the oxide film maybe related to the thickness. And it influent the future prosthetics on implant. The stability and corrosive-resistance of the anodic oxide film was much higher than that of natural oxide film. Anodic oxidation is a good way to enhance the pure titanium corrosive-resistance in vitro.