Erosion wear behavior and mechanism of high-content SiC/epoxy composites

Abstract The erosion behavior of polymer composites filled with high-content ceramic particles exhibits distinct characteristics compared to low-filled systems. In this study, high-filled epoxy/SiC composites with SiC mass fractions ranging from 77.8% to 87.0% were successfully fabricated using silane coupling agent surface modification and vacuum centrifugal deaeration. The erosion behavior of the composites was systematically investigated at different impact angles (30°–90°). The results show that with increasing SiC content, the erosion mechanism transitions from semi-ductile (maximum erosion at 45°) to brittle (maximum erosion at 90°). The transition occurs between 81.1% and 84.2% (55–65 vol%), which coincides precisely with the random close packing limit of polydisperse spheres, revealing that the formation of the densely packed SiC particle network governs the mechanism shift. At low impact angles (30°–45°), the erosion rate of high-content samples is unexpectedly lower than that of low-content samples, which is attributed to the physical shielding effect induced by densely packed SiC particles—a structural effect that is independent of the overall compressive modulus. In contrast, under normal impact (90°), the high-content samples exhibit a significantly higher erosion rate due to interfacial embrittlement and loss of matrix continuity. This study reveals the dual nature of erosion behavior in highly filled composites and provides a theoretical basis for erosion-resistant design under oblique impact conditions.