Enhanced electromagnetic interference shielding properties of carbon fiber veil/Fe₃O₄ nanoparticles/epoxy multiscale composites

The multiscale approach has been adapted to enhance the electromagnetic interference shielding properties of carbon fiber (CF) veil epoxy-based composites. The Fe₃O₄ nanoparticles (NPs) were homogeneously dispersed in the epoxy matrix after surface modification by using silane coupling agent. The CF veil/Fe₃O₄ NPs/epoxy multiscale composites were manufactured by impregnating the CF veils with Fe₃O₄ NPs/epoxy mixture to prepare prepreg followed by vacuum bagging process. The electromagnetic interference shielding properties combined with the complex permittivity and complex permeability of the composites were investigated in the X-band (8.2–12.4 GHz) range. The total shielding effectiveness (SE_T) increases with increasing Fe₃O₄ NPs loadings and the maximum SE_T is 51.5 dB at low thickness of 1 mm. The incorporation of Fe₃O₄ NPs into the composites enhances the complex permittivity and complex permeability thus enhancing the electromagnetic wave absorption capability. The increased SE_T dominated by absorption loss SE_A is attributed to the enhanced magnetic loss and dielectric loss generated by Fe₃O₄ NPs and multilayer construction of the composites. The microwave conductivity increases and the skin depth decreases with increasing Fe₃O₄ NPs loadings. (paper)