Influence of fiber coating on electromagnetic wave absorption properties of SiCf/epoxy composites
Structure modulation at multiscale is critical for optimizing electromagnetic wave absorption (EWA) in fiber-reinforced composites. This study employs two SiC fibers with distinct resistivities: L-fiber (~3 Ω·cm) and H-fiber (~7×10^5 Ω·cm). To tailor impedance, BN single coating and SiO2/BN dual-coating were applied to L-fibers. Unidirectional prepregs were stacked in various sequences to fabricate composites. Results demonstrate that both fiber coatings and stacking architecture significantly affect EWA performance. Computational optimization guided the design, yielding stacked composites with reflection loss (RL) below −10 dB across the entire X-band (8.2–12.4 GHz) and Ku-band (12.4–18.0 GHz). Notably, surface coatings on L-fibers substantially widen the thickness range over which stacked composites maintain excellent performance. Dual-coating outperforms single coating in broadening this available thickness range. These findings provide a robust strategy for engineering high-performance EWA composites through multiscale structural control.