Water-Lubricated Friction Properties of C/C-SiC Composites with Different SiC-Phase Contents Fabricated by RMI

Carbon fiber–reinforced silicon carbide matrix (C/C-SiC) composites with different SiC contents were fabricated by reactive melt infiltration of silicon with four types of porous C/C composites prepared by chemical vapor infiltration. Compared to high-density C/C composites and silicified graphite, the C/C-SiC composites demonstrated an excellent balance of mechanical properties, especially impact toughness. The results show that the porosity of C/C composites is a key factor that affects the SiC content in the C/C-SiC composites. A W18Cr4V steel alloy (hardness 55–60 HRC, roughness 0.8 μm) was used as the material for the friction pair. The friction coefficient of the C/C-SiC composites measured by block-on-ring friction tests is mainly influenced by SiC content and test load. The friction coefficient first increases and then decreases as the SiC content and test load increase, reaching a minimum of 0.011 for 44.22 vol% SiC composite under a load of 80 N. Water also plays an important role in decreasing the friction coefficient. Observations of the worn surface and wear debris indicate that the main wear mechanism of C/C-SiC composites is abrasive wear.