Properties of hybrid carbon – FeCo composites

Hybrid composites of carbon component/nanosized FeCo particles were synthesized from solution by the co-precipitation method (multiwalled carbon nanotubes, graphene nanoplates, carbon black and carbon fiber were used as the carbon component, and the presence of phases of carbon substrates, cobalt, iron and its oxide forms was found. FeCo nanoparticles with sizes from 5 nm form agglomerates of 50–100 nm on the surface of carbon substrates; the localization of metal particles is characteristic of each substrate, which is associated with the distribution of active functional groups on the surface. The dielectric behavior of the composites in the microwave range and at low frequencies has been studied. It has been shown that carbon fiber/FeCo composites with ?? and ?" significantly exceeding the values of individual components have a significant interface between the components in the composite and a more uniform distribution of metal particles on the surface of carbon fiber compared to other substrates. All the composites obtained have pronounced magnetic properties and thermally stable to a temperature of 250 °C. The frequency dependences of absorption and reflection coefficients in the range from 1 to 40 GHz for the composites obtained are calculated. Several absorption mechanisms are realized simultaneously in the composites (absorption above -12 dB), which makes them an attractive component for creating effective electromagnetic radiation absorbers for different ranges.