Investigation of the influence of composition ratio of nano/micro FeCo alloy particles on the electromagnetic wave absorption performance

Abstract Four sets of FeCo binary alloy magnetic particles were prepared with liquid phase reduction, and the impact of changes in Fe:Co element content on the microstructure and electromagnetic absorption properties were discussed. The results showed that with an increase in Fe content, the particle size decreased and crystallinity increased. The real and imaginary parts of the complex permittivity of the samples were stable at low frequencies (2–10GHz) but resonances at high frequencies (10–18GHz), demonstrating good dielectric loss capability at specific microwave frequencies. As frequency increased, the real part of the complex magnetic permeability of some samples were stable at low frequencies but fluctuated at high frequencies, while the real part of the permeability of some samples decreased gradually. When the Co content exceeded that of Fe, the imaginary part of the permeability exhibited peaks with high frequencies. As frequency increased, some samples displayed the characteristics of eddy current loss while the other samples exhibited characteristics of exchange resonance. Also polarization relaxation loss was observed. The sample Fe:Co ratio of 4:6 presented the best reflectivity loss of −9.98 dB at frequency of 14 GHz with a sample thickness of 2.6 mm.