Dielectric enhancement effect in biomorphic porous carbon-based iron@iron carbide'meta-powder'for light-weight microwave absorption material design

In this paper, biomorphic porous carbon-based composite powder, in which Fe@Fe3C core-shell nanoparticles embedded periodically, was fabricated by morphology genetic method. The morphology, microstructure, dielectric properties, and the microwave absorption performance of the composite powder were characterized in detail. The results indicate that the coupling effect among the neighboring core-shell nanoparticles will be strengthen in the case of ordered distribution, leading to leading to an unconventional permittivity enhancement phenomenon. This coupling effect will enlarge the energy consumption capacity of the composite powder, which offer a promising prospect for the light-weight microwave absorption materials (MAM) design. According to the experimental results, the effective absorption bandwidth (RL < -10 dB) has been enlarged to 5.6 GHz, and the minimum reflection loss reached up to -50 dB at 8 GHz. Moreover, by using 'meta-powder' as the absorbent in MAM, the usage amount of the absorbent can be reduced by half without causing negative effect to the microwave absorption performance.