TRIBOFILM FORMATION DURING DRY SLIDING OF GRAPHITE- AND MOS2- BASED COMPOSITES obtained BY SPARK PLASMA SINTERING

Abstract Composites of Astaloy 85Mo with the addition of MoS2, graphite or a mixture of graphite/MoS2 were consolidated using Spark Plasma Sintering. Dry sliding wear tests were conducted at different normal loads (5, 10, and 20 N) using the sintered samples against an AISI 52100 ball. The effect of contact pressure on the extrusion of solid lubricant was investigated using scratch tests. Graphite addition to the matrix provided the formation of a tribofilm, which lead to the lowest values of friction and wear. For the MoS2-composites, the formation of iron sulfides and oxidative products resulted in an increase in the friction coefficient at the highest normal loads. For the MoS2/graphite-composite, the samples exhibited an intermediate friction coefficient and the highest hardness.