TiO₂ Nano-tube about 30 μm Prepared by Anodic Oxidation

In order to prepare longer TiO₂ nano-tube, Ti sheet was anodically oxidized at direct voltage of 20 V in solution of 0.5(mass fraction)% NaF＋glycerin for 7 h, at the temperature of 0 ℃, 20 ℃ and 40 ℃ respectively. The results of SEM show that the length of the TiO₂ nano-tube was 1.034 μm, 2.601 μm and 5.152 μm for 0 ℃, 20 ℃ and 40 ℃ respectively. The results of current density show that balance anodic current density in the solution of 0.5 NaF+glycerin at temperature of 20 ℃ and 40 ℃ was 1.27 mA/cm² and 1.50 mA/cm² respectively. At the temperature of 40 ℃, in solution of 0.5% NaF+glycerin, TiO₂ nano-tube could grow to about 30 μm for 36 h of anodic oxidation.