Preparation and electromagnetic wave absorption properties of Fe₃O₄@TiO₂-CNTs/BF composite materials

To address the longstanding challenge of achieving both broadband, strong electromagnetic absorption and lightweight, high-strength performance in conventional absorbers, basalt fibers (BF) were introduced as a structural framework, and a hierarchical core-shell Fe₃O₄@TiO₂-CNTs architecture was employed as the absorbing component to fabricate Fe₃O₄@TiO₂-CNTs/BF composites (FTC-O/BF). The phase structure and morphology were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. The electromagnetic wave absorption performance was evaluated using a vector network analyzer in combination with numerical simulations. The results demonstrate that when the Fe₃O₄@TiO₂∶CNTs mass ratio is 5∶1 and the thickness is 5 mm, the composite exhibits a saturation magnetization of 26.8 emu·g-1, a minimum reflection loss (RL_min) of −66.8 dB, and an effective absorption bandwidth (EAB) of approximately 2.2 GHz. The FTC-O/BF composite prepared at this optimized ratio exhibits dual-band absorption characteristics at a thickness of 16 mm, with RL_min values of −55.3 dB in the 13-17 GHz range (EAB = 3.6 GHz) and −50.6 dB in the 7-11 GHz range (EAB = 3.5 GHz). The synergistic integration of Fe₃O₄@TiO₂ and CNTs significantly enhances magnetic loss, conductive loss, and interfacial polarization. This study provides a feasible strategy for the preparation of high-performance, tunable electromagnetic-absorbing BF composites.