Structure of nanotubular titanium oxide templates prepared by electrochemical anodization in H2SO4/HF solutions

The electrochemical formation of nanotubular titanium oxide films was investigated in 1 M H₂SO₄ and 0.05-0.4 wt.% HF electrolytes. Depending on anodization condition, i.e. cell voltage, anodization time, HF concentration, TiO₂ porous films having different thickness (from 350 to 500 nm) and pore diameter (from 40 to 150 nm) were obtained. By varying the cell voltage from 10 V to 40 V it was possible to gradually change the crystal structure of titanium oxide from anatase to rutile. The effect of annealing temperature and duration on crystal structure was also considered.