Tribological properties of oscillatory pressure sintered SiC-based ceramics: Influence of load and sliding speed

Abstract

The wear resistance of SiC-based ceramics is a crucial factor influencing their service life when they are used in the field of tribological engineering. Here, the influence of external factors (load and sliding speed) on the tribological properties of SiC-based ceramics prepared by oscillatory pressure sintering was explored together with an analysis of the wear mechanism of such ceramics. As the applied load increased from 20 N to 60 N, the surface roughness of specimens continuously increased. The corresponding wear mechanism underwent a change from plowing and plastic deformation to material fracture and abrasive wear. Furthermore, the wear rate of the specimen with 1 wt% graphene nanosheets (GNPs) and 5 wt% SiC whiskers (SiCw) increased from 3.15 ± 0.05 × 10⁻⁷ mm³·N⁻¹·m⁻¹ to 4.23 ± 0.09 × 10⁻⁷ mm³·N⁻¹·m⁻¹. As the sliding speed increased (2–6 m/min), the friction process generated a considerable amount of heat, resulting in an elevated surface temperature of the specimen; a more complete relief structure was formed on the wear surface, reducing the contact area of the specimen and thus enhancing the wear resistance of the specimen. The most favorable tribological performance of SiC-1 wt% GNPs-5 wt% SiCw ceramics in cyclic dry friction was attributed to the self-lubrication effect of GNPs and the enhancement of mechanical properties of SiC-based ceramics.