Development of an efficient microwave-absorbing material based on epoxy nanocomposite containing Ni0.5Zn0.5Fe2O4-coated MWCNTs

The development of microwave absorbent is important because it enhances electromagnetic compatibility, reduces electromagnetic interference, and improves performance and safety in communication systems and electronic devices. In this study, a microwave-absorbing nanocomposite based on epoxy resin, containing nickel (Ni) and zinc (Zn)-doped Fe₃O₄ coated on multi-wall carbon nanotubes (epoxy/Ni_0.5Zn_0.5Fe₂O₄@MWCNTs), was prepared with varying nanoparticle content from 1 to 30 by wt%. X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) verified the successful synthesis of Ni_0.5Zn_0.5Fe₂O₄ nanoparticles. The saturation magnetization of Ni_0.5Zn_0.5Fe₂O₄ @MWCNTs was approximately 37 emu/g, with negligible remanence and coercivity, indicating that these nanocrystals exhibit ferromagnetic behavior. Transmission electron microscopy (TEM) was employed to analyze the dispersion of Ni_0.5Zn_0.5Fe₂O₄ nanocrystals on the surface of MWCNTs. TEM images revealed that the nanocrystals, averaging around 15 nm in size, are uniformly distributed on the outer surface of MWCNTs. Based on the mechanical test, the nanocomposite with 10 wt% of Ni_0.5Zn_0.5Fe₂O₄ @MWCNTs nanoparticle selected as an optimum sample. Moreover, thermal analysis of optimum sample showed outstanding thermal resistance for high-temperature microwave absorption applications. Reflection loss (RL) measurements indicated that the maximum RL values increased with nanoparticle content up to 10 wt%, but decreased at 30 wt%, highlighting an optimal loading for microwave absorption performance.