Influence of Fe₃O₄ and Carbon Black on the Enhanced Electromagnetic Interference (EMI) Shielding Effectiveness in...

The present study aims to investigate the shielding properties of the electromagnetic interference of polymer nanocomposites with different weight percentages of magnetite nanoparticles and cost-effective carbon black nanoparticle (CBN) on different thicknesses. X-ray diffraction test, Raman spectroscopy, the scanning electron microscopy, and the transmission electron microscope analysis were used for investigating the crystallographic structure, morphology and microstructure of the material. The nanocomposites were successfully prepared using a simple mixing and casting. Their shielding efficiency was measured by a vector network analyzer (VNA) in the frequency range of 8.2 ~ 12.4 GHz. The maximum total shielding efficiency was 36.6 dB at 8.2 GHz for a weight percentage of 15% Fe₃O₄ composite and 50% CBN (0.7 mm thickness). The results showed that with an increase of nanocomposite thickness, there is a shift of absorption shielding efficiency peak toward a higher frequency. In addition, nanocomposites had the greatest shielding effectiveness in the low-frequency range. It was found that the proper combination of electrical and magnetic losses causes excellent wave absorption. These findings indicated that epoxy resin with a combination of optimal weight percentage of magnetite and carbon black nanoparticle can be used as a suitable shielding in low thickness.