Abstract:

Sliding friction-wear properties of pressurelessly solid-state-sintered silicon carbide ceramics (SSiC) and liquid-phase-sintered SiC ceramics (LPSiC) pairing with tungsten carbide (WC) were researched under the frictions with or without lubrication. Under dry friction, as compared to LPSiC/WC pairs, SSiC/WC pairs have higher friction coefficient (μ) and less mass loss (Δm) due to SSiC ceramics have larger particle size and higher hardness. The surface topography of worn area was detected by SEM companying with elements mapping and micro-area XRD technology. The micro plough cut and micro fracture led to the wear of SiC ceramics. Its fatigue damage led to the wear of WC materials. The grinding-out WC grains were oxidized to amorphous WO₃ phase due to the friction heat generated in the friction. Under the wet friction with water as lubrication, as compared to SSiC/WC pairs, LPSiC/WC pairs have higher friction coefficient and less mass losses. Whether under dry friction or wet friction, the pairs with SiC ceramics as the fixed materials have lower μ and Δm than those with SiC ceramics as the rotated materials.

Key words: hard facing, sliding wear, friction pairs, surface topography, wear modeling