The wear behavior of a thin MoS_2 coating, as studied by triboscopic measurements in friction and electrical contact resistance

摘要

The wear resistance of thin MoS_2 layers has been extensively studied in the literature. The occurrence of material transfer, mechanical and tribochemical wear has been recently evidenced. Nevertheless, the high durability of this type of solid lubricant is still a matter of controversy. One explanation for this phenomenon is that friction and contact resistance are both controlled by material transfer processes. Then, the in vivomonitoring of the active interface, i.e. during sliding, is found as being a major technical issue. In this paper, we present some results concerning the monitoring of the interface by the means of electrical contact measurements in a reciprocating sphere on plane friction test. Thanks to spatially-resolved mechanical and electrical measurements, we give evidence for debris removal and recirculation through the contact. Based on a simplified model of interface, we correlate the evolution of interfacial thickness and remaining material, as analyzed by EDS. The dependence of the tribological behavior to environmental change is then probed. We precise some limits of this method in the case of moisture.