Investigation on the Dielectric Properties of Exfoliated Graphite-Silicon Carbide Nanocomposites and Their Absorbing Capability for the Microwave Radiation

The dielectric properties of the exfoliated graphite (EG) and sillicon carbide (SiC) powder based epoxy nanocomposites are investigated in the microwave frequency region for radar absorbers and stealth applications. The resulting composites are found to possess high dielectric constant and loss tangent in the X band (8.2-12.4 GHz) frequency region. It is observed that both the dielectric constant and the loss tangent of the nanocomposites increase as the weight percentages of the EG and SiC powders are increased. SiC powder is mainly introduced to enhance the thermal stability of the nanocomposites with the improved microwave absorption properties. The filler percentages of SiC nanopowder and EG powders are optimized for the wide band electromagnetic absorption (EM). Maximum EM absorption of 99.99% along with the minimum absorption value of 90% is achieved throughout X band frequency region. The resulting nanocomposites possess a very good agreement between the light weight, ease of processing, and cost. Furthermore, the complete morphological and thermal stability analyses are carried out for the nanocomposite samples which provide an insight into various mechanical and thermal properties. The observed electromagnetic, mechanical, and thermal properties of the proposed nanocomposites make them potential candidates as efficient electromagnetic absorbers in the microwave frequency region for various strategic applications.