HIGH TEMPERATURE TRIBOLOGICAL PROPERTIES OF SPARK-PLASMA-SINTERED Al2O3-SrSO4 SELF-LUBRICATING NANOCOMPOSITES INCORPORATED WITH AND WITHOUT Ag ADDITION

摘要

Spark plasma sintering (SPS) is employed to fabricate self-lubricating Al2O3-SrSO4 nanocomposites incorporated with and without Ag addition. The friction and wear properties have been evaluated using a high temperature friction and wear tester from room temperature to 600°C in dry sliding against alumina ball. X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX) analyzer were used to investigate microstructure and self-lubrication mechanisms of nanocomposites after wear tests at different temperatures. Al2O3-SrSO4 nanocomposites with optimum compositional combinations exhibit low and stable friction coefficients of 0.22 and wear rates in the order of 10-5 mm3/Nm at high temperatures. At low temperature, the Ag additives in the composite form a discontinuous lubricating film to effectively reduce friction and wear. With increasing test temperature, plastic deformation of SrSO4 during sliding plays an important role in formation of lubricating films on worn surfaces to reduce the friction and wear.