Lightweight and salt spray corrosion resistant porous SiC/FeSiCr hybrids for enhanced microwave absorption in the C-band

Lightweight, high-strength –electromagnetic(EM) absorption materials are in pressing requirement in both military and civilian fields. Porous silicon carbide (SiC) has attracted increasing attention as an EM absorption material. However, it’s absorption performance is still limited. In this work, the SiC foam/FeSiCr composites were prepared by a simple sacrificial template method coupled with an immersion process. FeSiCr particles were anchored on the three-dimensional porous SiC skeletons with polyurethane resin serving as a binder. Benefiting from the multiscale synergistic effect and coating strengthening efficacy, the obtained SiC foam/FeSiCr hybrids exhibited excellent EM absorption properties and high mechanical strength. Especially, the SiC foam/FeSiCr-40 sample possessed the best EM absorption ability with a minimum reflection loss (RLmin) value of −31.2 dB at 4.3 GHz at a thickness of 5 mm. Meanwhile, it also had a relatively high compressive strength of 5.62 MPa which was superior to that of the pure SiC foam (3.25 MPa). Moreover, the SiC foam/FeSiCr composites exhibited preferable salt spray corrosion resistance properties due to the chemical inertness of SiC and FeSiCr particles. Due to their excellent overall performance, SiC foam/FeSiCr composites have a great potential for application as structural absorption materials in ocean environments with high salt fog atmosphere. In addition, this work also provides guidance regarding the design and preparation of other structural absorption materials.