Synthesis of Fe@Ni nanoparticles-modified graphene/epoxy composites with enhanced microwave absorption performance

High performance microwave absorber consisting of Fe@Ni nanoparticles (NPs) modified reduced graphene oxide (RGO) and epoxy resin was successfully prepared. Fe@Ni NPs obtained via electroless plating method could be simply anchored on the surface of RGO sheets because of its high surface area, as well as residual organic groups of RGO. The crystal/micro-structure and magnetic properties of as-synthesized samples were subsequently analyzed by XRD, SEM, TEM, XPS and VSM, while electromagnetic properties were tested by vector network analyzer. The synergistic effect between graphene and Fe@Ni NPs generated suitable impedance match and strong microwave attenuation ability which lead to excellent microwave absorption property. The optimal reflection loss (RL) calculated from measured electromagnetic parameters can reach up to - 22.7 dB at 14.9 GHz with a layer thickness of 2 mm. Moreover, RL values < - 10 dB is found to be 5.5 GHz within 12.5-18 GHz, almost covering the entire Ku band. It's convincing that the as-synthesized composites are potential candidates for high-performance lightweight microwave absorbers.