Synergistic effect of polyhedral iron-cobalt alloys and graphite nanosheets with excellent microwave absorption performance

Fast development of industry and technology has led to electromagnetic harm in the civil and military field, which has been obtained much attention and can be effectively weakened with the help of microwave absorbing materials. Hence, based on the route that multiple materials can optimize the impedance matching to further improve the microwave absorption performance, the polyhedral iron-cobalt alloy (FeCo)/graphite nanosheets (p-FCG) binary composites were prepared by the speedy and facile liquid reduction method. SEM results show polyhedral FeCo alloys with the size of 100–200 nm are located on the surface of graphite nanosheets (GNS), forming the stable three-dimensional structure. When the filled ratio is 40 wt% in the epoxy resin, the maximum reflection loss reaches −53.96 dB and the efficient bandwidth is 4.3 GHz with a thin thickness of 1.3 mm. More importantly, the effective bandwidth of p-FCG is able to cover the entire C, X and Ku bands with the matching thicknesses in the range from 1.3 mm to 4.2 mm. The microwave absorption performance of p-FCG is remarkable, which is superior to the single GNS and FeCo on account of synergistic effect and moderate impedance matching. Thus, the binary composites p-FCG may be expected as an engineering microwave absorber with the strong absorption, thin thickness, and wide frequency.