High graphene fillers content for improving the tribological performance of silicon nitride-based ceramics

The effect of large graphene nanoplatelets (GNPs) additions on the friction and wear of silicon nitride (Si3N4) ceramics is evaluated under isooctane lubrication. All Si3N4/GNPs composites, with up to 20.6 vol% of graphene fillers, exhibit better tribological response than Si3N4, in particular, a 50% reduction in the friction that continuously decreases with the GNPs content is attained, jointly with an improvement in the wear resistance of up to 63%. The survival of a self-lubricant carbon-rich tribolayer formed on the worn surfaces controls the tribological properties of the materials. Si3N4/GNPs composites are promising materials to enhance the performance of gasoline direct injection systems.This work was supported by projects MAT2015-67437-R(MICINN,FEDER,UE) and RTI2018-095052-B-I00 (MICINN