Dielectric behavior of Fe3N@C composites with green synthesis and their remarkable electromagnetic wave absorption performance

Multiple loss mechanisms of conductive loss, interface polarization loss, dipolar polarization and magnetic resonance loss endow excellent performance of Fe3N@C composites. [Display omitted] •Fe3N@C hybrid composites were synthesized by using amino acids as nitrogen sources.•The relaxation times were calculated by Debye theory to investigate dielectric behavior of hybrid composites.•The optimal performance with RLmin of −77.6 dB and EABmax of 7.76 GHz were achieved. Fe3N has been considered as a new generation of ideal ferromagnetic materials with the virtues of high saturated magnetization and high resistance to oxidation. However, a facile and eco-friendly fabrication of Fe3N still needs to be investigated. Herein, the gelatin derived from fish skin was chosen as the raw material of carbon and the amino acid inherent in fish skin can act as a nitrogen source for the generation of Fe3N. Besides, the influence of graphitization degree to dielectric behavior of composites was further investigated. In this work, the composites fabricated by 0.8 mmol Fe(NO3)3 exhibited optimal absorption performance with the minimum reflection loss of −77.6 dB at 2.2 mm. Besides, the absorption bandwidth was detected as 7.76 GHz (covering from 10.24 to 18 GHz) at the matching thickness of 2.7 mm. According to the analysis of dielectric constant, the degree of graphitization affects the dielectric behavior mainly in determining the orientation speed of the dipole and the conductive loss. This work provides a new thought for the investigation of the electromagnetic absorption mechanism of composite.