Tribological properties of Ti-based (Ti, TiO2 and TiN) films on the stainless steel (304SS) substrate were investigated in the atmosphere of N2, O2 and air at several pressures. Films 0.2 μm thick were prepared on the mirror-polished substrate with an ion beam assisted deposition method, an ion beam assisted reactive deposition method and the dynamic ion mixing method. Tribological tests were carried out with a friction tester of Pin-On-Disk type in a high vacuum equipment. The wear surface was observed with an optical microscope, a scanning laser microscope and a scanning electron microscope.
The friction coefficients of stainless steel, Ti, TiO2 and TiN film increased with decreasing a pressure and those except of stainless steel converged on 0.3 in a pressure of 1 × 10-3 Pa. In an O2 atmosphere, the behavior of the Ti film in a friction coefficient for a pressure was similar to that of the TiO2 film, and in a N2 atmosphere, the friction coefficients of Ti and TiN film showed the same value. These results suggested the relation between a kind of a gas atmosphere in the tribological test and the film element.