Tribological properties of anatase TiO2 sol-gel films controlled by mutually soluble dopants

Tribological properties of TiO2 sol-gel thin films with mutually soluble dopants were studied on a glass substrate. The results showed that the formation of mutually soluble solid solution played a very important role in the growth of titania grains. The fine-grained TiO2 films controlled by SiO2 dopant were superior to pure TiO2 film in wear resistance and endurance life, although both films greatly improve the surface characteristics of glass substrate, enhancing its tribological characteristics. High resistance to microfracture because of the very small grain size as well as a good adhesion of the film to the substrate is believed to be the determining factors influencing the tribological properties of SiO2 doped TiO2 films. However, excessive SiO2 seriously deteriorates wear resistance of film due to phase separation. The wear mechanisms were also discussed based on the observation of the surface morphologies by scanning electron microscope (SEM).