Tribological Properties of Cashew Nut Shell Liquid Modified Phenolic Resin Matrix Composites Reinforced with SiC and ZnO Particles

Cashew nut shell liquid modified phenolic resin matrix composites synergistically reinforced with SiC and ZnO particles at different mass ratios （1∶3, 1∶2, 1∶1, 2∶1, and 3∶1, with a total filler content of 15%） were fabricated by hot-press sintering method. The micromorphology, thermal stability, mechanical and tribological properties of the composites were investigated. The results show that all prepared composites were dense, with the presence of grooves, gaps, and pits at the interfaces. As the mass ratio of SiC to ZnO particles increased, the types of phases remained unchanged, the dispersion of each phase first decreased, then increased, and finally decreased again; the relative density was reduced; the mass retention rate at 600 ℃ and the 5% mass loss first decreased, then increased, and subsequently decreased; hardness and compressive strength initially increased and then decreased, and the average friction coefficient increased; the volumetric wear rate first decreased and then increased, with the wear mechanism transitioning from abrasive wear to adhesive wear, then to fatigue wear, and back to abrasive wear. When the mass ratio of SiC to ZnO particles was 2∶1, the phases were uniformly dispersed and tightly bonded. At this ratio, the composite exhibited the highest mass retention rate at 600 ℃, the maximum 5% mass loss, the greatest hardness and compressive strength, a moderate average friction coefficient, and the lowest volumetric wear rate, demonstrating optimal thermal stability, mechanical, and tribological performance.