Enhanced microwave absorption properties of Fe73.5Cu1Nb3Si15.5B7 nanoflakes by moderate surface oxidization and rotational orientation in composites

Fe73.5Cu1Nb3Si15.5B7 nanoflakes were fabricated by ball milling the annealed ribbons. The microwave absorption properties of Fe73.5Cu1Nb3Si15.5B7 nanoflakes were improved by moderate surface oxidization and rotational orientation in composites. As for the oxide-coated nanoflakes composite, the permittivity decreased distinctly and the permeability maintained the initial value compared with the as-milled nanoflakes composite. Through rotational orientation, the lower permittivity and higher permeability were obtained, and consequently the microwave absorption properties were improved obviously. The minimum reflectivity for the absorber of the oriented composites with 35 vol% oxide-coated nanoflakes could reach −46.4 dB at 1.31 GHz with the thickness of 4.2 mm.

► Fe73.5Cu1Nb3Si15.5B7 nanoflakes were fabricated by ball milling the annealed ribbons. ► The nanoflakes were moderately oxidized to decrease the permittivity. ► The rotational orientation for composite was employed to further increase the permeability. ► The enhanced microwave absorption properties of Fe73.5Cu1Nb3Si15.5B7 nanoflakes were obtained by moderate oxidization and rotational orientation in composites.