Control Over the Growth of Titania Nanotubes by Anodisation of TI Foil in NH4F-Containing Electrolyte

摘要

TiO_2 nanotubes were produced by anodisation of pure titanium foil in a standard two-electrode bath consisting of either 1M Na_2SO_4 or glycerol solution containing 5wt% NH_4F. The effect of anodisation voltage applied to the foil was studied to investigate the possibility of controlling the dimensions of the nanotubes produced. It was found that, in both electrochemical baths the diameter of the nanotubes increases with increasing of the applied voltage. However, in 1M Na_2SO_4 there appears to be a maximum voltage at which the nanotubular structure persists. The maximum applied voltage must be less than 30V. Above this voltage, the nanotubular structure is destroyed leaving an oxide with porous-like morphology. In glycerol bath, the maximum voltage is higher. The length of the nanotubes was also found to be dependent on the voltage. In glycerol, the length of the nanotubes increases from 200nm to 700nm as the anodisation voltage was increased from 10 to 30V.