Microwave Absorbers Based on Fe and Fe–Al Particles Obtained in the Field of Rotational Magnetic Dipoles

The purpose of the work is to obtain microwave absorber materials based on Fe–Al particles and to study its absorbing characteristics. Composite materials consisting of Fe, Fe–Al particles, and a paraffin matrix were obtained by the rotating magnetic field method. The mechanism of usage of magnetic dipoles for coating Fe particles with Al nanoparticles and further composite material synthesis was described. The microstructure, mechanical, magnetic, and dielectric properties and parameters of microwave absorption of the obtained composite materials were investigated. Magnetic and dielectric permittivity in the frequency range of 8–12 GHz were obtained. The influence of the field of rotational magnetic dipoles in combination with Al nanoparticles makes it possible to obtain a more durable structure in comparison with composite materials without Al nanoparticles. It was found that composite materials have good radio-absorbing properties in the studied frequency range. The maximum value of S21 = –27.9 dB was obtained at a frequency of 12 GHz for an Fe–Al composite material with application of the field of rotational magnetic dipoles.