Microwave Absorption Properties of Carbon Black/Silica Sol Dual‐Component Modified SiC Fiber Felt

ABSTRACT Due to their low density, high‐temperature resistance, and tunable electrical resistivity, SiC fibers have shown great potential as promising microwave absorption (MA) materials. However, the poor impedance matching and limited electromagnetic loss mechanisms of intrinsic SiC fibers result in a relatively narrow effective absorption bandwidth, thereby limiting their practical applications. Based on a strategy for synergistic multiple loss mechanisms, SiO 2 /carbon‑black modified Ni–SiC (SiO 2 /CB/Ni–SiC) composites were fabricated via an electrospinning‐vacuum impregnation‐drying process. Conductive carbon black and low‐dielectric SiO 2 layers were coated onto the Ni–SiC fiber skeleton, significantly improving the electromagnetic wave (EMW) absorption capacity of fiber felts. The optimal loadings of CB and silica were 12 wt.% and 8%, respectively. Benefiting from the optimized impedance matching induced by SiO 2 , the SiO 2 /CB/Ni–SiC fiber felt exhibited a maximum effective absorption bandwidth (EAB max ) of 7.68 GHz (10.32–18 GHz) at a thickness of 2.5 mm, along with a minimum reflection loss (RL min ) of −51.56 dB at 8.48 GHz, which demonstrates superior EMW absorption performance. Therefore, a simple, low‐cost approach to enhancing the absorption performance of SiC fiber felt has been identified.