Synthesis and microwave absorption properties of sandwich microstructure Ce2Fe17N3-δ/expanded graphite composites

Sandwich microstructure composites composed of Ce 2 Fe 17 N 3-δ and different mass fractions of expanded graphite (0, 1, 2, 3 wt%) were prepared, and their microwave absorption properties were studied. The microscopic morphology, composition, soft magnetic properties , chemical structure , electromagnetic parameters, and absorption properties of the Ce 2 Fe 17 N 3-δ /EG composites were analyzed. The results show that Ce 2 Fe 17 N 3-δ is an irregular particle with an average particle size of about 3 µm and EG is a multi-layer structure with an average interlayer spacing of about 2.7 µm. The saturation magnetization ( M s ) value of Ce 2 Fe 17 N 3-δ is 135 emu/g, and the coercivity ( H c ) is 53 Oe. The effect of the loading of expanded graphite in the Ce 2 Fe 17 N 3-δ /EG composites on their microwave absorbing properties is discussed. It was found that the well-designed two-component and appropriately loaded expanded graphite endowed the Ce 2 Fe 17 N 3-δ /EG composites with excellent absorption properties. When the mass fraction of expanded graphite was 1% and the thickness of the absorber was 1.42 mm, the reflection loss reached −67.3 dB at 14.9 GHz with an effective bandwidth of 5.74 GHz. Compared with other expanded graphite-based absorbing materials, Ce 2 Fe 17 N 3-δ /EG composites exhibited better electromagnetic wave absorption performance at a lower thickness. The enhancement of the absorption performance is attributed to the optimization of impedance matching and the synergistic action between multiple loss mechanisms.