Anodized Titanium Production Using Titanium Oxide Suspended in Sulfuric Acid Electrolyte and Evaluation of Hydroxyapatite Formation in Simulated Body Fluid

Anodized titanium plates were produced as implant material, using powdered titanium oxide suspended in sulfuric acid aqueous solution electrolyte. Based on X-ray diffraction (XRD) and Auger electron spectrometry analyses, the formation of approximately 2800-nm-thick surface oxide film on titanium consisting of rutile and anatase phases was confirmed. This oxide film on titanium contained many submicron-size pores. The anodized titanium plate was immersed in simulated body fluid, and evaluated using scanning electron microscopy and XRD. Low-crystalline hydroxyapatite formed on the surface after seven days of immersion. In contrast, a 270-nm-thick oxide film was produced on titanium plate anodized in phosphoric acid aqueous solution. In this instance, no additional layer was observed on the surface even after seven days of immersion in simulated body fluid. The biocompatibility was presumed to have improved in the titanium plate anodized using titanium oxide suspended in sulfuric acid aqueous solution electrolyte, because of the formation of a thick oxide film that contained a large number of pores. This material was thus found to be promising for use in implants.