Abstract:

The anodization of high-purity titanium was carried out via a potentiostatic approach in 0. 1 mol /L H₂SO₄ solution,with a traditional three-electrode cell,a high-purity titanium plate,a platinum electrode and a saturated Ag /AgCl electrode respectively as the template,the working electrode,the counter electrode and the reference electrode. Then,the effects of anodization potential and oxidation time on the formation and crystallization characteristics of the anodic titanium oxide films were analyzed,and the films were characterized by means of SEM-EDS,Raman spectroscopy and XPS. The results show that there exist anatase-phase TiO₂ nano-crystals in the films prepared via an anodic oxidation at 6V,60min or at 30V,10min,and that high anodization potential and long oxidation time both promote the transformation of intermediate titanium oxides to stable titanium dioxide and accelerate the formation and growth of the anatase-phase nano-crystals,thus resulting in a structural evolution of the anodic titanium oxide films from a short-range ordered structure with few TiO₂ nano-crystals to a long-range one mainly composed of anatase-phase TiO₂ .

Key words: titanium, titanium dioxide, anodic oxidation, crystallization, potentiostatic mode