Fe–Fe3C/C microspheres as a lightweight microwave absorbent

Abstract

As electromagnetic pollution is becoming more and more serious, novel composite microwave absorbents are gaining much attention. In this work, low-cost glucose was used as a carbon source to prepare hydrochar, and Fe–Fe₃C/C microspheres for microwave absorption were successfully synthesized through the hydrothermal synthesis of Fe₃O₄/hydrochar and subsequent high-temperature carbonization at different temperatures. The results showed that the Fe–Fe₃C nanoparticles were uniformly loaded on the carbon microspheres. Resulting from the synergistic effect of Fe–Fe₃C nanoparticles and partially graphitized carbon, a wide region of microwave absorption was achieved due to dual dielectric and magnetic losses. An effective bandwidth of reflection loss less than −10 dB could reach up to 4 GHz with 1.5 mm thickness. Owing to the characteristics of the cost-effective synthetic route, low density and good microwave absorption with thin thickness, the Fe–Fe₃C/C microspheres could be used as a lightweight and highly efficient microwave absorbent.