Microstructure, strength and tribological behavior of Fe–C–Cu–Ni sintered steels prepared with MoS₂ addition

Powder metal processing permits development of new composites with specific properties required for demanding applications. Complex shaped machine elements like gears and bearings are made of powder metallurgy technique economically. In many applications these machine elements operate under unlubricated conditions and there is a need for materials with good friction and wear characteristics, strength and modulus. In the present study, Fe–C–Cu–Ni alloys with solid lubricant, MoS₂, were developed using a simple single stage compaction and sintering. The microstructure, strength, hardness and tribo behavior of the composites were evaluated. The friction and wear characteristics were evaluated using pin-on-disc type tribo test machine. Addition of solid lubricant improved the compressibility and thereby the density of the compacts. Presence of the secondary sulphide phases in the as-sintered compacts improves the hardness and strength. The coefficient of friction and wear loss decreased with addition of MoS₂. A simple wear model is proposed to predict the wear loss in these composites. The model predicts wear loss values that are in agreement with the experimental data.