Thermal stability of TiO₂ nanotube array films

Titanium dioxide nanotube array films on Al plates were prepared by liquid phase deposition (LPD) method. The sampies were annealed at various temperatures. The phase and microstructure of the nanotube array films were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). It is found that the phase of as-deposited TiO₂ array film without heat treatment is amorphous, but there is anatase in the film after heattreating at 400℃ for 2 h. The structure of TiO₂ array film after annealed at 650℃ for 2 h in air is still stable, The presence of alumina promotes the thermal stability of TiO₂ nanotube array films and suppresses the growth of crystal grains and primary particles.