Microwave Behavior of α-Fe/Fe_3B/Y_2O_3 Nanocomposites in GHz Range Prepared by Melt-Spun Technique

摘要

Nanocomposites α-Fe/Fe_3B/Y_2O_3 were prepared by a melt-spun technique, and the electromagnetic wave absorption properties were measured in the 0.05 ～ 20.05 GHz range. Compared with α-Fe/Y_2O_3 composites, the resonance frequency (f_r) of α-Fe/Fe_3B/Y_2O_3 shifted to a higher frequency range due to the large anisotropy field (H_A) of tetragonal Fe_3B (～0.4 mA·m~(-1)). The relative permittivity (ε_r = (ε_r)′ - (jε_r)″) was constantly low over the 0.5 ～ 10 GHz region, which indicates that the composite powders have a high resistivity (ρ = ～100 Ωm). The effective electromagnetic wave absorption (RL < - 20 dB) was obtained in a frequency range of 2.7 ～ 6.5 GHz on resin composites of 80% (mass fraction) α-Fe/Fe_3B/Y_2O_3 powders, with thickness of 6 ～ 3 mm respectively. A minimum reflection loss of -33 dB was observed at 4.5 GHz with an absorber thickness of 4 mm.