Tribological properties of Ni-based self-lubricating composites with addition of silver and molybdenum disulfide

Tribological properties of Ni-based composites containing silver and molybdenum disulfide were studied from room temperature to 700 degrees C. The composites were prepared by powder metallurgy technique and the phase composition and microstructure were addressed according to the characterization by SEM and XRD. The results show that the composites were composed of Ni, Cr2O3, Ag and CrxSy phases after sintering. The best tribological properties were obtained when the silver and molybdenum disulfide contents were 20 wt% and 8.5 wt%, respectively. The tribo-chemical reaction occurred between Ag and Mo oxide during the rubbing process, which led to the formation of silver molybdate lubricating film. The improved tribological properties were attributed to the formation of silver molybdate lubricating tribolayers. (C) 2012 Elsevier Ltd. All rights reserved.