An investigation on the microwave absorption properties of Co–Al–Ti substituted barium hexaferrite-MWCNT nanocomposites

Abstract

Abstract The microwave absorption properties of Co-Al-Ti substituted barium hexaferrite-multiwalled carbon nanotubes (MWCNTs)-epoxy resin nanocomposites are thoroughly investigated in the frequency range of 1-18\xa0GHz. The Nanoparticles with the chemical formula Ba Co x Al x Ti x Fe 12 − 3 x O 19 x = 0.2 , 0.3 , and 0.4 are synthesized by the sol-gel auto combustion method. The XRD patterns along with Rietveld analysis as implemented in FullProf software are used to characterize crystalline nanoparticles. The effect of the substitution on the magnetic properties of the nanoparticles is also investigated by the VSM analysis. The MWCNTs are then dispersed into the nanoparticles by high-power ultrasonic waves to fabricate nanocomposite structures. All of the nanocomposites show appropriate microwave absorption properties with a matching thickness lower than 1.75\xa0mm. The reflection loss minimum is also lower than -20dB in which more than 99.9% of the electromagnetic wave energy is absorbed. The bandwidth of the nanocomposites covers practically the whole frequency range of 1-18\xa0GHz by changing the thickness of the samples. The reflection loss minimum (RLmin) reaches − 47.40 dB for the sample with x=0.3, and the nanocomposite with x=0.2 shows the best microwave absorption performance with the bandwidth of 4.59\xa0GHz at the matching thickness of only 1.5\xa0mm. Therefore, these nanocomposites can be used as microwave absorbers with high efficiency, and small weight and thickness.