MoS₂-Au/Au multilayer lubrication film with better resistance to space environment

MoS₂-Au/Au multilayer film was sputtered and exposed in low earth orbit environment aboard Chinese Shenzhou-7 manned spaceship to develop a solid film combining good lubricity and space-environment resistance together. The results revealed that space exposure caused the oxidation of MoS₂-Au/Au multilayer film, but which was restricted into film surface. Importantly, the delaminating behavior was not observed from the space-exposed MoS₂-Au/Au multilayer film, which was normal for other MoS₂/metal multilayer film. As a result, the space-exposed MoS₂-Au/Au multilayer film still exhibited a good lubricity (friction coefficients at ∼0.02–0.05), but a relatively high initial friction coefficient about 0.08 due to the surface oxidation. These results indicated that this multilayer lubrication film had a good capability resistant to space environment and potential application as solid lubricant in space technology.