Preparation, characterization and microwave absorbing properties of FeNi alloy prepared by gas atomization method

Highlights: ► Spherical Fe–50 wt%Ni particles with the phase composition of FCC (Fe, Ni) alloy were synthesized by nitrogen gas atomization method. ► The as-atomized FeNi alloy possesses low coercivity and high specific saturation magnetization. ► As the frequency increases, the permeability and real part of permittivity of the silicone rubber absorbers filled with 48 vol% Fe–50 wt%Ni decrease, and the imaginary part of permittivity increases. ► The Fe–50 wt% Ni alloy/silicone rubber absorbers exhibit adjustable microwave absorbing properties in the range of 1–18 GHz. - Abstract: In this work, Fe–50 wt%Ni alloy was synthesized by nitrogen gas atomization method. The phase composition, morphology, element composition and saturation magnetization of the alloys were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence spectrometer (XRF) and vibrating sample magnetometer (VSM). The electromagnetic parameters and microwave absorbing properties of the microwave absorbing material made from silicone rubber and the as-prepared FeNi alloy were also studied using vector network analyzer (VNA) and transmission line theory. The results show that the particle size of most of the particles is less than 150 μm, and the average particle size is about 48 μm. The Fe–50 wt%Ni powder has a spherical shape, and the main phase composition is FCC (Fe, Ni) alloy. The as-atomized FeNi alloy possesses low coercivity and high specific saturation magnetization. As the frequency increases, the real part of relative permittivity and relative permeability of the Fe–50 wt%Ni/silicone rubber absorber decrease, while the imaginary part of relative permittivity increases. The Fe–50 wt% Ni alloy/silicone rubber absorbers with 0.8–4 mm thickness exhibit adjustable microwave absorbing properties in the range of 1–18 GHz.