Microwave electromagnetic and absorption properties of SmN/α-Fe/Sm2Fe17N3 composites in 0.5–18 GHz range

SmN/α-Fe/Sm2Fe17N3 composites were prepared in situ by heating of Sm2Fe17N3 powders, and their electromagnetic wave absorption properties were measured in the frequency range of 0.5–18 GHz. The result shows that saturation magnetization and coercivity of as-heated powder with 23.7 wt% SmN, 58.5 wt% α-Fe and 17.8 wt% Sm2Fe17N3 are 130.82 emu/g and 750 Oe, respectively. The dielectric constant of composites was low over the frequency range of 0.5–18 GHz, and their resonance frequencies were at a high frequency range. The effective electromagnetic wave absorption (RL < −20 dB) of the compact sample with thickness of 0.7–3.2 mm prepared with the SmN/α-Fe/Sm2Fe17N3 and resin was obtained in a frequency range of 5.5–16 GHz. A minimum reflection loss of −33 dB of the samples was observed at 5.5 GHz with an absorber thickness of 3.2 mm.