Preparation of Carbon Nanotube/Carbonyl Iron Nanocomposites and Investigation of Their Electromagnetic Waves Absorbing Properties at Radar Frequency Band

Use of microwave absorbers and radar-absorbing materials is one of the growing needs in military and civilian applications. Weight reduction, improvement of absorbing characteristics, high microwave absorption and wide operating bandwidths are important issues in absorbing materials. One of the most suitable compounds is nanocomposite of carbon nanotubes/magnetic metals. In this work, nanocomposites of carbonyl iron (CI) and multi-walls carbon nanotubes (MWCNT) with different %Wt via homogeneously mixing with paraffin were prepared and their microwave absorbing properties were investigated in the frequency range of 8-18 GHz. SEM and XRD images of nanocomposites showed uniform dispersion of MWCNT and CI particles in the matrix. Also, the results of wave absorption showed that by increasing of iron carbonyl respect to carbon nanotubes and the formation of carbon nanotube-based nanocomposite absorbers, the absorption and absorption bandwidth increase. For the nanocomposite containing 70% by weight of carbonyl iron, the highest amount of reflection loss was 11.33 dB at the frequency of 18 GHz. Also, in the bandwidth of 10.1 GHz to 18 GHz, the amount of reflection loss was obtained more than 4 dB.