Synthesis and GHz Range Microwave Absorption Properties for Fine Nano-composite Powders of Iron-based Alloys or Compounds

摘要

Fine nano-composite-powders of iron-base-d alloys or compounds were synthesized from the Y_2Fe_(17), Y_2Fe_(77.5)B_(17.5)by hydrogenation and the subsequent oxidation and/or nitrogenation, e.g. alpha-Fe/Y_2O_3, Fe_xB/Y_2O_3), epsilon-Fe_3N/Y_2O_3, and alpha-Fe-Fe_xB/Y_2O_3. While the resin composite of alpha-Fe/Y_2O_3 showed good absorption characteristics for the microwaves in a range of 2.0-3.5 GHz, those of Fe_xB/Y_2O_3, epsilon-Fe_3N/Y_2O_3, and alpha-Fe-Fe_xB/Y_2O_3 also gave the strong absorbing profiles but they were widened and shifted to high frequency side, viz. 0.6-4.4 GHz, 2.7-6.5 GHz, and 2.7-6.5 GHz. respectively. This is mainly due to their high magnetic anisotropy (2 pi f_r=gamma H_A) and the f_r values evaluated from the profiles of alpha-Fe/Y_2O_3, Fe_xB/Y_2O_3, epsilon-Fe_3N/Y_2O_3, and alpha-Fe-Fe_xB/Y_2O_3 are 0.95/2.6, 1.8, and 4.5 GHz, respectively.