Effect of UV irradiation on wear protection of TiO2 and Ni-doped TiO2 coatings

The relationship between UV photoinduced hydrophilicity and tribological performance of the thin films of pure and Ni-doped TiO2 was investigated in this paper. The films were prepared on a glass substrate by sol-gel and spin coating process from specially formulated ethanol sols. The chemical structure and morphologies of the films surface were observed with X-ray photoelectron spectroscopy (XPS), X-ray Diffraction (XRD) and atomic force microscope (AFM). The tribological properties of obtained thin films, when sliding against steel ball, were evaluated on a one-way reciprocating friction tester. It is clearly observed that UV irradiation resume the hydrophobicility of the films of pure and Ni-doped TiO2, however greatly worsen their wear protection properties.