Enhanced tribological properties of Y/MoS2 composite coatings prepared by chemical vapor deposition

Abstract

Chemical vapor deposition (CVD) is an efficient approach to prepare coatings on complex cutting tools. However, MoS2 with self-lubrication ability and excellent tribological properties fabricated by CVD have been rarely reported in literature. The aim of this study was to deposit pure MoS2 coatings and yttrium (Y) doped MoS2 (Y/MoS2) composite coatings on cemented carbide blades coated with titanium nitride by CVD. The structural and mechanical properties of the coatings were examined by scanning electron microscopy (SEM) and nanoindentation, respectively. The results demonstrated that the microstructure of Y/MoS2 composite coatings was denser than that of the pure MoS2 coating. The hardness and the adhesional properties were significantly enhanced for the Y/MoS2 composite coatings. The tribological performance of the as-deposited coatings were investigated under atmospheric environment. Y/MoS2 compostite coatings demonstrated an enhanced tribological performance with a stable and low coefficient of friction (COF) over the entire sliding time. In contrast, the COF of pure MoS2 coating dramatically increased to value above 0.3 after a sliding time of only 30 min. Additionally, the Y/MoS2 composite coatings showed a decreased wear rate (8.36 +/- 0.29 x 10(-7) mm(3)/Nm) compared to the pure MoS2 coatings (3.41 +/- 0.48 x 10(-5) mm(3)/Nm) thus reflecting an improvement by two order of magnitude.