Bimetallic coupled porous SiC for multi-band and high-temperature electromagnetic wave response

Developing electromagnetic wave (EMW) absorption materials with multi-band response is a daunting challenge for new electronic devices and radar stealth due to the intrinsic dielectric or magnetic properties of the material. Particularly, traditional multi-band responsive magnetic composite has become a research bottleneck due to magnetic decay at high temperatures. Herein, we use dielectric SiC derived from the ordered mesoporous silicon template to combine with magnetic metal compounds to achieve multi-band response characteristics and high-temperature absorption performance that traditional SiC-metal composite absorbers cannot achieve. The constructed bimetal-doped SiC composite inherits abundant components (SiC, FeSi, and CoSi), unique structures, and numerous defects (vacancies and stacking faults), which promote the multi-band response behavior of CoSi/SiC and FeSi/CoSi/SiC composites, covering the C, X, and Ku bands. The FeSi/CoSi/SiC composites achieve a reflection loss (R_L) value of − 53.13 dB at a matching thickness of only 1.63 mm. Furthermore, FeSi/CoSi/SiC composite still maintains outstanding EMW absorption performance after high-temperature oxidation (550 ℃). Experimental results and theoretical analysis show that the multi-level structure, abundant defects and heterointerfaces, and magnetic elements in the composite contribute to its impedance matching, dielectric loss, and magnetic loss capabilities, thus promoting multi-band response characteristics. Therefore, this work provides a strategy for constructing multi-band responsive materials, which can provide initiatives for other fields such as dielectrics, optical responses, and flexible electronics.