Co decorated polymer-derived SiCN ceramic aerogel composites with ultrabroad microwave absorption performance

Ultra-wide absorption bandwidth is one of the goals of ideal absorbing materials. In this article, three-dimensional porous microstructure Co/SiCN ceramic aerogel composites (CACs) were synthesized through a reverse microemulsion method, which is aimed to avoid the aggregation of cobalt nanoparticles, and makes better impedance matching between CACs surface and air to obtain an outstanding microwave absorption (MA) performance. The complex permittivity of the CACs could be tuned via the concentration of cobalt acetate solution. The MA results indicate that CACs with cobalt acetate solution concentration of 0.5 mol/L shows an excellent MA properties with ultrabroad bandwidth 8.5 GHz covering the whole K band (18–26.5 GHz). The excellent MA performance can be attributed to good impedance matching, multiple reflections, polarization processes, and the synergistic effects in the CACs. Therefore, our study paves a novel way to fabricate the promising lightweight MA materials with ultrabroad absorption bandwidth at higher frequency.