Preparation of bioactive titania films on titanium metal via anodic oxidation

ObjectivesTo research the crystal structure and surface morphology of anodic films on titanium metal in different electrolytes under various electrochemical conditions and investigate the effect of the crystal structure of the oxide films on apatite-forming ability in simulated body fluid (SBF).MethodsTitanium oxide films were prepared using an anodic oxidation method on the surface of titanium metal in four different electrolytes: sulfuric acid, acetic acid, phosphoric acid and sodium sulfate solutions with different voltages for 1 min at room temperature.ResultsAnodic films that consisted of rutile and/or anatase phases with porous structures were formed on titanium metal after anodizing in H2SO4 and Na2SO4 electrolytes, while amorphous titania films were produced after anodizing in CH3COOH and H3PO4 electrolytes. Titanium metal with the anatase and/or rutile crystal structure films showed excellent apatite-forming ability and produced a compact apatite layer covering all the surface of titanium after soaking in SBF for 7 d, but titanium metal with amorphous titania layers was not able to induce apatite formation.SignificanceThe resultant apatite layer formed on titanium metal in SBF could enhance the bonding strength between living tissue and the implant. Anodic oxidation is believed to be an effective method for preparing bioactive titanium metal as an artificial bone substitute even under load-bearing conditions.