Hybridized-carbon-based materials with magnetic metals and oxides have attracted much attention because of their enhanced electromagnetic wave loss. In this study, magnetic particles were coated on the surface of carbon fibers by carbonizing in a nitrogen atmosphere. The morphology, structure, thermolysis, and wave-absorption performance of the carbon fiber/magnetic particle composite were determined. Results show that the in situ-formed magnetic particles (such as Fe₃O₄, NiFe₂O₄, CoFe₂O₄, and Ni₃Fe) are uniformly dispersed along the carbon-based fibers, which exhibit different wave absorption. The absorption of the carbon fiber/magnetic particle composite can be controlled by adjusting the species and concentration of the magnetic particle coating, which provides a new and effective way of endowing the magnetic-particle-coated carbon fibers with good microwave absorption properties.

A three-layered electromagnetic (EM) wave-absorbing material was prepared by depositing a Fe ₃ O ₄ and boron nitride (BN) coating onto the surface of a carbon fiber (CF) by in situ hybridization.

In this study, the porous activated carbon fiber (ACF) is prepared by viscose fiber, and Fe₃O₄ coating is deposited on the surface of ACF through in situ hybridization to prepare carbon/magnetic electromagnetic (EM) wave absorption materials. Compared with pure Fe₃O₄ and ACF, the EM wave absorption rate is improved. When the solubility of FeCl₃ is 2 mol/L and the thickness of the prepared ACF–Fe₃O₄(3) EM wave absorption material is 3 mm, the EM wave loss at 10 GHz reaches −44.3 dB and effective EM wave absorption bandwidths ( dB and dB) reached 4.8 GHz (8.8–13.6 GHz) and 1.1 GHz (9.3–10.4 GHz), respectively. The prepared ACF-based composite material has a light structure and strong absorption bandwidth. Findings can provide references for the research on other EM wave-absorbing materials.

An electromagnetic (EM) wave-absorbing material with a three-layer structure is prepared by depositing magnetic particles and a high-temperature resistant coating on the surface of the carbon fiber (CF) with in situ hybridization. Accordingly, the structure, chemical composition, morphology, high-temperature resistance, EM characteristics, and EM wave absorption of the composite materials were analyzed. The composite materials contained CFs, and the magnetic particles, such as Fe₃O₄, NiFe₂O₄, CoFe₂O₄, and Ni₃Fe, distributed along the axial direction of the fiber, while boron nitride (BN) existed in the outermost coating layer. This preparation method improves the oxidation resistance and EM wave absorption performance of the CF. When the concentrations of the metal salt solution and the original BN solution are 0.625×1.5 mol L^-1 [nFeCl3: nCoSO4: nNiSO4=2:2:1] and 4 mol L^-1 [nH3BO3:nCONH22=1:3], respectively, the thermal decomposition temperature of the prepared CF/1.5FeCoNi/2BN is increased from 450°C to 754°C. In the frequency range of 10.6–26 GHz, the EM wave loss is less than −10 dB (the bandwidth spans 15.4 GHz). The CF-based composite material prepared in this study has the characteristics of light weight, wide absorption band, and strong oxidation resistance and constitutes the reference basis for the study of other high-temperature, EM wave-absorbing materials.