Electromagnetic wave absorption properties in Ku-band of magnetic iron nitrides prepared by high energy ball milling

Abstract Gas nitriding and high-energy ball milling were adopt to prepare iron nitrides samples. The iron nitrides samples with different nitrogen contents and different magnetic properties were obtained through mixing with different ingredients with high-energy ball milling process. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), vibrating sample magnetometer (VSM) and vector network analyzer (VNA). The iron nitrides samples were nanostructured and contained lots of interfaces, boundaries and defects inside the particles. The electromagnetic wave reflection loss (RL) value was simulated according to transmission line theory by using the samples’ electromagnetic parameters. The sample with a saturation magnetization of 173.3 emu∙g-1 had the best RL value, which reached -63.31dB at 17.93 GHz with a thickness of 1.77 mm. The samples with Ms value greater than 90.9 emu∙g-1 could effectively absorb electromagnetic waves in the Ku band. The absorption performance decreased with the decreasing Ms value. The nanostructure obtained by high-energy ball milling was discussed to be beneficial for improving the permittivity and the permeability of the iron nitrides samples in the Ku band. The electromagnetic wave absorption mechanisms were also analyzed. In addition, this study offers a reference for industrially producing electromagnetic wave absorbing materials with low cost.