Mechanical and wave absorption properties of Fe₃O₄‐deposited Buckypaper reinforcing epoxy resin composites

Abstract There are increasing need for the development of electromagnetic wave‐absorbing materials since the growing concern about electromagnetic interference. However, materials with integrated structure and function are difficult to attain due to the high content of functional fillers. In this paper, carbon nanotubes (CNTs) were formed into a three‐dimensional porous framework, known as Buckypaper (BP), which was subsequently in situ deposited with iron tetraoxide (Fe₃O₄) through the sol–gel method and incorporated into epoxy resin to create Fe₃O₄/BP/EP composites by hot pressing. The three‐dimensional porous structure of Fe₃O₄/BP facilitates the high‐content incorporation and uniform dispersion of CNTs and Fe₃O₄ nanoparticles. The results indicate that the 33%Fe₃O₄/BP/EP composite achieved an optimal reflection loss of −38.41 dB and an absorption bandwidth of 3.28 GHz at the optimal matching thickness of 1.5 mm. This performance primarily stems from Fe₃O₄ adjusting the impedance matching of BP and enhancing the magnetic loss capability of CNTs. Furthermore, the deposition of Fe₃O₄ on BP improves the mechanical strength of BP/EP, The 17% Fe₃O₄/BP/EP composite achieves a tensile strength of 35.09 MPa, which is 46.27% higher than that of BP/EP and 92.38% higher than pure EP. Highlights Fe₃O₄/BP was prepared by deposition of Fe₃O₄ onto surfaces of the CNTs framework. Fe₃O₄/BP/EP composites with different Fe₃O₄/BP were fabricated. Fe₃O₄ adjusts impedance matching of BP, and forms heterogeneous interfaces. Fe₃O₄/BP/EP composites exhibit excellent wave absorption performance. Fe₃O₄/BP/EP composites possess improved mechanical properties.