EFFECT OF CeO2 NANOPARTICLES ADDITION ON TRIBOLOGICAL BEHAVIOR OF AUSTENITIC DUCTILE IRON

In order to improve the wear resistance of austenitic ductileiron (ADI), varying amounts (0, 0.25, 0.5 and 0.75 wt%) of CeO2 nanoparticles are added to austenitic ductile iron through lost foam casting, and the tribological behavior of austenitic ductile iron is studied through a ball-on-disk sliding test with a tungsten carbide (WC) counter ball. It is found that CeO2 nanoparticles can refine the graphite structure and simultaneously introduce a greater number of low-angle grain boundaries within the austenite. This improves the mechanical properties of austenitic ductile iron. Austenitic ductile iron exhibits the optimal hardness (207(-7)(+12 )HV5). ultimate tensile strength(452(-9)(+7) MPa) and elongation (14.4%) with a CeO2 content of 0.5 wt%. Due to the increased hardness, its wear resistance is significantly improved, with an 85% reduction in wear volume. During the friction process, graphite fractured by CeO2, along with the nanoparticles, serves as solid lubricants. The oxide layer produced by frictional heat on the worn surface can also provide lubrication, thereby reducing the coefficient of friction. The hardened layer formed beneath the surface due to strain hardening further contributes to the enhancement of wear resistance of austenitic ductile iron.