Hollow spherical SiC@Ni composites towards the tunable wideband electromagnetic wave absorption

Combining dielectric substrates and magnetic materials is a practical approach to improve electromagnetic wave (EMW) absorption performance due to the dielectric and magnetic synergy loss effect. In this work, uniform monodisperse hollow SiC@Ni (H–SiC@Ni) composites were synthesised through a simple route, including the sacrificial templating method and the subsequent reduction reaction. Different contents of Ni₃S₂ and Ni could be obtained by adjusting the volume and reaction temperature, which are closely related to the electromagnetic parameters and absorption capabilities. The results show that the H–SiC@Ni-750 composite reaches the optimum EMW absorption performance with the minimum reflection loss of −55.7 dB at 7.3 GHz and the effective absorption bandwidth (EAB) of 8.8 GHz at 2.6 mm. The high absorption performance of the H–SiC@Ni-750 composite benefits from the synergistic dielectric loss and magnetic loss of SiC and Ni nanoparticles. In addition, the hollow and monodisperse core-shell structure of the samples can increase the transmission path through multiple reflections and scattering and further dissipate the EMW energy. This work provides a facile pathway to prepare H–SiC@Ni composite with broadband electromagnetic absorption performance.