Fe–Fe₃C/C Fibers as a Highly Efficient Microwave Absorbent

As electromagnetic pollution is becoming more and more serious, novel composite microwave absorbents are gaining much attention. In this work, Fe–Fe₃C/C fibers were successfully synthesized by using low-cost cotton as carbon source. The synthetic route was an easy and flexible two-step approach consisting of immersion and subsequent carbothermal reduction in N2 atmosphere. The results showed that the Fe–Fe₃C nanoparticles were uniformly loaded on the cotton-based carbon fibers. Resulting from the synergistic effect of magnetic loss from Fe–Fe₃C nanoparticles and dielectric loss from cotton-based carbon fibers, a wide region of microwave absorption was achieved. When the thickness is 1.5 mm, the minimum reflection loss (RL) is −28.3 dB, and the effective bandwidth of RL less than −10 dB could reach up to 4.2 GHz. Owing to the characteristics of cost-effective synthetic route, low density, low filling rate and good microwave absorption with thin thickness, the Fe–Fe₃C/C fibers could be used as a practical microwave absorbent.