The magnetic and microwave absorbing properties of the as spun Nd-Fe-Co-B nanocomposites

•Magnetic and electromagnetic properties of quenched Co-doped NdFeB alloys were studied.•The quenched Co-doped NdFeB alloys exhibit a single α-Fe phases soft magnetic properties and have excellent absorbing properties at 2–18 GHz. In this paper, microstructure, magnetic and microwave absorbing properties of NdxFe85−xCo4B11 nanocomposites (x=3, 5, 7, 9) flaky-shaped particles prepared by melt spun were investigated. The analyses of XRD spectra suggest that all samples only have the single α-Fe phase. With the increase of the Nd content, the complex permittivity-frequency and permeability-frequency were increased at first, and then decreased with higher Nd content. The resin composites of 70wt% of these nanocomposite powders showed excellent electromagnetic wave absorption properties in GHz range. A minimum reflection loss of −23.1dB is obtained at 9.8GHz for composite Nd9Fe76Co4B11.