Influence of Anodization Time and Voltage on the Parameters of TiO₂ Nanotubes

A vertically aligned titania nanotube layer was obtained by electrochemical anodic oxidation in the electrolyte contained 0.4 wt% solution of NH₄F in 54 ml of ethylene glycol and 5 ml of deionized water, after titanium was chemically cleaned/etched with a mixture of HCl, H₂O and HNO₃ solution for removing the natural oxide films. The morphology and composition of the titania nanotube layer were examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The anodization of TiO₂ nanotubes was done using 60 V for 240 min and 30 min, and 30 V for 30 min. The diameter of the titania nanotubes was about 52-156 nm, the wall thickness about 32-53 nm and the height about 0.9-6.3 μm. The pore size of TiO₂ nanotubes influences the dissolution rate of CaP thin films and Young's modulus, which is significantly lower than that of the Ti substrate. Our future challenge will be investigation of the microstructure and mechanical behavior of titania nanotubes with CaP film.