Long-range-ordered Fe3Al with excellent electromagnetic wave absorption

Long-range-ordered Fe3Al was prepared by a mechanical alloying and ordering transformation process. Different ball milling time in the mechanical alloying process induces various amounts of long-range-ordered DO3-type Fe3Al, leading to different magnetic properties. It was found that with the increase of ball milling time, the saturation magnetization values increased to 149 emu/g and then decreased to 96 emu/g. Interestingly, their electromagnetic wave absorption properties are also different. The complex permeability curves are characterized by multiple peaks, which is attributed to the natural resonance. In particular, Fe3Al powder obtained by a 30 h ball milling process is a promising candidate for thin electromagnetic wave absorber, with the minimum reflection loss of - 41.5 dB at the 12.1 GHz when the thickness is 1.5 mm, and the bandwidth below - 10 dB is 4.8 GHz.