Preparation Of TiO₂ Coated Glass At Low Temperature And Investigation Of The Micromechanical Properties

Nanocrystalline TiO2 thin film with different thickness was deposited on LSG and UV-cut glass and then heat treated at different temperatures. The effects of heat treatment temperature, film layers and substrates on the structures, the micromechanical, optical properties and photocatalysis of film were investi- gated with the Fourier infrared spectrometer (FT-IR), Differential scanning calorimetric and thermo gravimetric analysis (DSC-TG), X-ray diffractometer (XRD), Field emission scanning electronic microscopy (FESEM), Atomic force microscope (AFM), UV-vis spectrophotometer and the nanoindentation test. The photocatalysis of film is characterized by degradation rate of Methyl Orange.The results indicate that TiO2 contained in sol is anatase phase, the average grain size is 21.4 nm. With the heat treatment temperature increasing to 550℃, TiO2 crystal structures are still anatase phase, the average crystal size increases to 31.2 nm. When the temperature is increased, the packing density of TiO2 film increases, the roughness decreases, film makes more smooth, the nanohardness, plasticity index and the adhesion strength increase, and the friction coefficient decreases. After heat treated at 500℃, the nanohardness of TiO2 film increases to 1.0 GPa and 1.2 GPa, the plasticity index increases to about 0.3, the friction coefficient is 0.195 and 0.178, respectively. The adhesion strength of TiO2 film with 1 layer heat-treated at 500℃deposited on LSG increases from 1584μN to3980μN, and from 1741μN to above 4500μN deposited on UV-cut glass.The transmittance of LSG and UV-cut coated glass is high to about 80 % in the visible region and low to about 5 % in the ultraviolet region. The ultraviolet absorption band of LSG coated glass is 340 nm, and the maximum of absorbance moves to more layers with the increasing tempereature. The absorbance of LSG coated glass heat treated at 500℃with 5 layers increases to about 2.66. The ultraviolet absorption band of UV-cut coated glass broadens to 380 nm, and that the absorbance finally keeps to about 2.84. The degradation rate of Methyl Orange placed LSG coated glass with 5 layers heat treated at 350℃reaches to 51.67 % after ultraviolet radiation for 60 min.