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The work reports on the morphologies and the tribological properties of MoS 2 films deposited onto the as-deposited or textured TiN and WC interlayers. The closed-field unbalanced magnetron sputtered MoS 2 film exhibited dense structure without obvious voids or columnar morphology. Meanwhile, plenty of MoS 2 nanowires or nanorods were grown on the film surface. With the laser-textured TiN or WC interlayer introduced, both the textured TiN/MoS 2 film and WC/MoS 2 film exhibited a long lubricating life higher than 8.0 × 105 sliding cycles, much higher than that for the un-textured films or pure MoS 2 film. • MoS 2 films with textured TiN, WC interlayer were deposited by a closed-field unbalanced-magnetron sputtering system. • The deposited MoS 2 film exhibited a dense structure with plenty of nanowires or nanorods grown between the MoS 2 columnar. • The textured TiN/MoS 2 film and WC/MoS 2 film exhibited a long lubricating life higher than 8.0 × 105 sliding cycles. [ABSTRACT FROM AUTHOR]

Many failures and anomalies of spacecrafts originated from space environmental factors. Meanwhile, MoS 2 based films have been widely used in space technology as solid lubricants. In this paper, the compact MoS 2 -Sb 2 O 3 composite film was rf-sputtered and exposed in low earth orbit (LEO) environment, which was aboard the exterior of Shenzhou-7 Manned Spaceship (SZMS-7). The results revealed that the space exposure effect on MoS 2 -Sb 2 O 3 composite film mainly exhibited the oxidation at the film surface layer less than 3.5 nm. No severe oxidation and cracking phenomena were observed from the space-exposed MoS 2 -Sb 2 O 3 composite film, which was normal for many space materials. Namely, the MoS 2 -Sb 2 O 3 composite film exhibited a better capability resistant to LEO space environment. [ABSTRACT FROM AUTHOR]

The microstructure and wear resistance of sputtered MoS 2 films can be improved by adding some amount of metals. However, the oxidation-resistance of MoS 2 -metals films would be worried because some metals are sensitive to atomic oxygen (AO). In this paper, the inert Sb 2 O 3 was introduced into the MoS 2 film, and its effect on the structure and anti-oxidation ability of the MoS 2 film was clarified. XRD and SEM results revealed that due to the addition of Sb 2 O 3 , the growth of MoS 2 micro-platelets was almost suppressed, and so the composite film was amorphous and very compact. XPS analysis indicated that for the composite film, the influence by the AO irradiation was restricted into the film surface layer. Namely, the composite film exhibited a better anti-oxidation ability in the AO environment. [ABSTRACT FROM AUTHOR]

The rf-sputtered MoS 2 -Au composite films were exposed in real low earth orbit (LEO) space environment by a space environment exposure device (SEED) aboard China Shenzhou-7 manned spaceship. The ability of the composite films resistant to atomic oxygen (AO) was investigated using X-ray photoelectron spectroscope (XPS), X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) equipped with an X-ray energy dispersive spectroscopy (EDS). The results showed that the microstructure of the composite film was densified because the growth of MoS 2 platelets was suppressed to some content due to the addition of Au, although it was still characterized by a typical dendrite-like morphology. No obvious change in the morphology, phase structure, element composition and friction property was observed from the space exposed and non-exposed composite films, indicating that the composite film exhibited a better anti-oxidation ability as exposed in LEO environment. The improved anti-oxidation ability was attributed to the more compact microstructure and a passivation effect that the dangling bonds at the edge planes of MoS 2 platelets were probably occupied by the partial doping atoms. [ABSTRACT FROM AUTHOR]

Radio frequency-sputtered MoS 2 films had been exposed for 43.5 h in real low earth orbit (LEO) space environment by a space environment exposure device (SEED) aboard China Shenzhou-7 manned spaceship. The composition, morphology, phase structure and friction property of the exposed films were investigated using X-ray photoelectron spectroscope (XPS), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), X-ray energy-dispersive spectroscopy (EDS) and ball-on-disk tribometer. XRD and EDS results revealed that the as-deposited MoS 2 films were characterized by a MoS x O y phase structure, in which x and y values were determined to be ∼0.65 and 1.24, respectively. XPS analysis revealed that due to space atomic oxygen attack, the film surface was oxidized to MoO 3 and MoS x O y with higher O concentration, while the partial S was lost. However, the affected depth was restricted within the surface layer because of protective function of the oxidation layer. As a result, the friction coefficient only exhibited a slight increase at initial stage of sliding friction. [ABSTRACT FROM AUTHOR]