Synthesis and Characterization of Nickel Ferrite/Activated Carbon Nanocomposites as Radar Wave Absorbing Materials at X-Band Frequency

In this study, nickel ferrite/activated carbon nanocomposites have been fabricated using iron sand as radar wave absorbing materials at X-Band frequency. The formation of nanocomposites was confirmed by the appearance of Ni, Fe, O, and C elements obtained from the energy dispersive X-ray spectrum, which were the main constituent elements for nickel ferrite and activated carbon. In addition, X-ray diffraction characterization confirmed that the nickel ferrite/activated carbon nanocomposites had an inverse cubic spinel structure and a crystallite size of 11.10 nm. Scanning electron microscopy characterization showed that the nickel ferrite/activated carbon nanocomposites were irregularly spherical with an average particle size of about 46.12 nm. According to the vibrating sample magnetometer characterization, the saturation magnetization of the nanocomposites was 24.26 emu/g with superparamagnetic behavior of the nickel ferrite/activated carbon nanocomposites. Interestingly, the nickel ferrite/activated carbon exhibited a minimum reflection loss of −13.5 dB at a frequency of 7.24 GHz with an effective bandwidth of 1.11 GHz, along with an absorption efficiency higher than 90%. These results indicate that nickel ferrite/activated carbon nanocomposites exhibit promising potential as radar wave absorbing materials at X-band frequency.