Investigation of the friction and wear properties of Ti/TiB2/MoS2 graded-composite coatings deposited by CFUBMS under air and vacuum conditions

MoS2 coatings are effectively used in vacuum and in water vapor-free environments because of increased friction coefficient and decreased service life under atmospheric conditions. A lot of different alloy elements (e.g., Ti, Nb, Cr) and compounds (e.g., TiN, TiB2) are used to enhance the friction and wear properties of MoS2 coatings. In this study Ti/TiB2/MoS2 graded-composite coatings (GCC) were deposited by closed-field unbalanced magnetron sputtering (CFUBMS). The structural properties of the coatings were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The hardness of the coatings was measured with the use a microhardness tester. The tribological properties of the coatings were determined under air and vacuum conditions. Ti/TiB2/MoS2 (GCC) have MoS2 (002) and TiB2 (100) reflections. The coatings exhibited a dense and non-columnar structure. Tribological properties of the coatings under air and vacuum conditions significantly affected the hardness, thickness and stoichiometric ratio of elements in the structure.