Tribological behavior of graphene reinforced silicon nitride composites

Abstract

The tribological properties of silicon nitride + 1 wt. % graphene composites, prepared using gas pressure sintering (GPS) and hot isostatic pressing (HIP) at 1700 °C, were investigated and compared to the wear properties of monolithic Si3N4. The tribological measurements were performed using reciprocating ball-on-plate technique under dry conditions in the air with Si3N4 ball as a tribological partner at an applied load of 5 N and 13.5 N and sliding speed of 10 cm/s. Scanning electron microscopy (SEM) was used for the characterization of wear mechanisms. The friction coefficient of the systems changed from 0.40 to 0.47 and 0.55 to 0.69 at applied loads of 5 N and 13.5 N, respectively, with the lowest values for monolithic Si3N4 in both cases. The wear rates of investigated systems are in the range of 10-6 ~ 10-7 mm3 /N.m with the lowest wear rate for the monolithic silicon nitride prepared by GPS.