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.