Exploring the effect of V doping on the tribological mechanism of MoS2 coatings in atomic oxygen environment

MoS2 coatings are subject to severe oxidation and erosion under atomic oxygen (AO) irradiation due to its loose microstructure. This concern can be alleviated by means of metal doping. In this work, MoS2 coatings with different V doping content are deposited by magnetron sputtering. The morphology, chemical stability and tribological properties are investigated by scanning electron microscopy, energy dispersive spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, film stress tester and ball-on-disk tribometer, respectively. As the V doping content increases, the MoS2-V coating changes from a loose columnar crystal structure to a more dense structure. Friction and wear results show that the MoS2-V coating deposited at V target current of 0.5 A owns the best tribological properties with a friction coefficient of 0.04 and wear rate of 1.29 × 10−6 mm3/N·m under simulated AO environment. The objective is to develop MoS2-V composite coatings to AO irradiation resistance in order to select suitable lubricant for reliable space applications.