Impact of Ti-Doping on Tribological Properties of MoS₂ Coatings on Spacecraft Component

The Ti-doped MoS₂ coatings were deposited by mid-frequency unbalanced reactive magnetron sputtering on substrates of Si (100) and Ti-alloy. The influence of the atomic oxygen irradiation and Ti-doping on the microstructures and tribological behavior of the Ti-doped MoS₂ coatings was investigated with X-ray diffraction energy dispersive spectroscopy, scanning electron microscopy and high vacuum friction tester. The results show that the Ti-doping and O-irradiation had a major impact. For example, the oxidation-resistance and wear-resistance were increased and the friction coefficient was decreased, possibly because the atomic oxygen fully oxidized the Ti-dopant in the < 002 > preferentially grown grains of Ti/MoS₂ coatings, increasing the surface compactness and service-life of the component. We suggest that the Ti-doped, O-irradiated MoS₂ coatings be of much technological interest in modification and lubrication of spacecraft-component surfaces involved.