The role of tribo-pairs in modifying the tribological behavior of the MoS₂/Ti composite coating

Mechanical contact conditions and the shear strength of the interface are the two independent factors that control the friction behavior of the MoS₂ coating. Although ZrO₂ and GCr15 had similar mechanical contact conditions, they showed rather different friction behaviors. Therefore, the shear strength of the interface was prominent in determining the friction behavior of the MoS₂/Ti composite coating, particularly in the initial stage of friction. The strong interfacial shear strength between GCr15, WC and MoS₂/Ti resulted in the high friction coefficient in air and short wear life in vacuum. Furthermore, we found that the interfacial shear strength was affected by the Ti content in the MoS₂/Ti coatings, and the adhesive behavior of Ti and GCr15 was responsible for the high friction coefficient and high wear rate. The shear strength between the two sliding materials was amplified with the increase in the vacuum degree. These results benefit us to tailor or select the MoS₂-based composite coatings and the corresponding tribo-pairs for vacuum operating conditions. (paper)