Structural evolution and wear resistance of MoS2-Based lubricant films irradiated by heavy ions

In this work, a 2 MeV Au2+ ion irradiation was implemented to simulate the neutron damage on magnetron sputtered MoS2-based composite films. The irradiation damage mechanism and the wear resistance of films were accessed as a function of increasing Au2+ fluence. The XRD as well as the cross-section TEM images results reveal that the intrinsic crystallites of MoS2 in Mo-S-Ti composite films are more easily to be destructed. At the low fluence of 1 x 10(14) Au2+/cm(2), the irradiation damage peak was mainly distributed in depth of 0.45 mu m - 0.7 mu m in films. While, with the increase of the incident fluence, the disordering of MoS2 crystallites near the film surface were also become serious, and they are fully amorphized at the end of the studied fluence of 3.3 x 10(15) ion/cm(2) due to the accumulation effect induced by the ion collisions. Nonetheless, the tribotests in vacuum show that the lubricity of MoS2 phases would not be immediately failured due to their damage of intrinsic structure of MoS2 crystallites, and only enhancing the irradiation to the high dose (2, 5 and 1 dpa), a rapid degradation of lubricity will be observed.