Effect of vacuum atomic oxygen irradiation on tribological properties of MoS2/WC multilayer films

The adaptability of molybdenum disulfide (MoS2) films in space environments is crucial for aerospace applications. However, atomic oxygen (AO) in low Earth orbit can damage the friction and wear performance of MoS2 films, leading to a reduction in the service life of the film. To enhance the resistance of the film to atomic oxygen irradiation, we constructed a nano-multilayer structure composed of MoS2-WC-MoS2. Studies have shown that MoS2/WC multilayer films exhibit an ultra-low friction coefficient of 0.010 due to their (002) preferred orientation. Even after high-dose AO irradiation at 1.84×1020 atoms·cm-2, the film still maintains a friction coefficient of 0.009. This is attributed to the presence of MeOX nanoparticles in the MoS2 transfer film at the friction interface after AO irradiation, and the existence of MeOX nanoparticles plays a key role in maintaining ultra-low friction of the film. These findings are of great significance for extending the service life of molybdenum disulfide films in space environments and enhancing their resistance to atomic oxygen irradiation.