SYNTHESIS OF MAGNETITE-FILLED NANOCOMPOSITE AS ELECTROMAGNETIC WAVE ABSORBING MATERIALS AT X- AND KUBAND FREQUENCY

To tackle the issue of electromagnetic (EM) pollution and EM interference, fabrication
of advanced, novel and superior microwave absorbing materials (MAM) with high EM
wave absorption, wide absorption bandwidth, lightweight and cost-efficient have
received huge attention. To date, magnetite (Fe3O4) is being thoroughly investigated as
MAM, due to its exceptional dual EM properties (permittivity and permeability), and
proper saturation magnetization. However, large density and impedance mismatch are
some of the limiting factors that hinder its EM wave absorption performance (EMAP).
Hence, with the expectation of an efficient microwave absorbing materials, the aim of
this research is to prepare Fe3O4-filled composites as enhanced MAM. Fe3O4
nanoparticles were prepared by a facile sol-gel method. Citric acid-coated Fe3O4
nanocomposites were prepared by coprecipitation method. Three-dimensional carboncoated
Fe3O4 composites (3DC@Fe3O4) were prepared by hydrothermal method.
Several characterization techniques were used to study the physiochemical properties
of the samples and the results were analyzed and presented. The EMAP of all samples
were studied at X-band (8.2-12.4 GHz) and Ku-band (12.4-18.0 GHz) Frequency range.
The 3DC@Fe3O4 composites display and enhanced EMAP with a minimum RL value
of -46.4 dB at 16.85 GHz with 2.0 mm absorber thickness. These good EMAP could be
attributed to structural advantages as well as favorable impedance matches derived from
the synergistic effect of proper dielectric loss from carbon microspheres and magnetic
loss contribution from Fe3O4 nanoparticles.