Effect of graphite and MoS2 based solid lubricants for application at wheel-rail interface on the wear mechanism and surface morphology of hypereutectoid rails

Abstract

The effectiveness of two graphite-based and one MoS2-based solid lubricants subjected to high creepages were experimentally assessed. This research correlated the evolution of coefficient of traction (CoT) to in-depth wear surface morphology and microstructure. The lubricating potential of these solid lubricants to reduce wear and thereby extend the operation life of rail components was comprehensively evaluated. The graphite-based lubricants were able to reduce the CoT and improve the wear resistance considerably. Furthermore, the graphite-based lubricant with lower carbon content was found to be effective at all tested conditions, offering 30%–55% reduction in CoTs, longer retentivity, and better surface morphology. However, the MoS2-based lubricant did not offer significant reduction in the CoT and resulted in substantial abrasive wear at higher creepages.