Friction and Wear Characteristics of Spark Sintered WC-Co-MoS<SUB>2</SUB> Alloys

Spark sintered WC-Co-5/10/20 vol%MoS2 alloys have been developed as self-lubricating cemented carbides. Using these alloys, friction and wear tests are performed in a ring(counterface: WC-22 mol%Co)-on-disk(specimen: WC-Co-MoS2) configuration in air. The dynamic coefficient of friction in the initial state of the test decreases with increasing MoS2 content in the specimens. In particular, this value is remarkably decreased by the addition of 5 vol%MoS2 to the alloy. The weight loss of the specimens shows a maximum value at 5 vol%MoS2. On the other hand, the weight loss of the counterface material decreases with increasing MoS2 content in the specimens. It is considered that the weight loss of the specimens is influenced by the following two factors caused by MoS2 addition. (1) Lubrication effect due to the formation of the film including MoS2; and (2) Accelerating effect of wear due to the increase of initial sites of fracture by the occurrence of depleted parts of MoS2 on the surface of the specimens.