Abstract: Nano Au-TiO₂ composite thin films were successfully fabricated by a facile sol gel process. The morphology, mircrostructure and properties of composite thin films were investigated via atomic force microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, UV-Vis optical absorption spectroscopy and one way reciprocating tribometer. The surfaces of thin film were uniform, compact and crack free. Au particles were well dispersed in TiO₂ matrix with a size of 14-25 nm in diameter. The composite thin films have a strong optical absorption. The peak position and intensity were related to the sintered temperature and the Au content. The composite thin films sliding against AISI 52100 steel ball displayed an excellent wear resistance and friction reduction reduction performance. With a 5.0%(molar fraction) Au, the friction coefficient was only 0.09-0.10 and the wear life was more than 2000 sliding cycles at a sliding speed of 90 mm/min and a load of 1.0 N.

Key words: Au-TiO₂ composite thin films, Sol gel process, Optical and frictional properties