Microwave absorption properties of CI and E-waste based heterogenous mixtures.

This work presents the study of effect of morphology of carbonyl iron, carbonyl iron-based, and e-waste-based mixtures on microwave absorption properties. Firstly, the flake shaped carbonyl iron particles and its mixture are prepared using conventional and efficient ball milling and blending method, respectively. It provides the absorption in lower frequency region. Further, the covered frequency range starts to shifts slowly towards higher frequency ranges due to the morphological changes. On the other hand, effect of complex morphology of e-waste-based mixtures are also studied. These heterogeneous mixtures are developed using the cutting mill and blending methods that can provide the absorption in higher frequency with very narrow bandwidth. In this manner, effect of morphology on single layer microwave absorption performance of developed heterogenous material is proposed. It is also explored that the developed samples cover a wider bandwidth by utilizing the multilayering technique. A three-layer absorber is designed using genetic algorithm and the results are also validated. The structural and morphological study of the developed heterogeneous materials has been done using X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) analysis. Also, rigorous study has been done on magnetic properties and Cole-Cole plots to understand the magnetic and dielectric losses respectively occurring inside the materials. The results showed wide bandwidth absorption of 11.62 GHz (≤−10 dB bandwidth) in the lower frequency region ranges from 0.5 to 12.12 GHz (i.e., L, C, and X-band). The total thickness achieved is 1.85 mm which is very compact (<2 mm). Thus, a thin and wideband microwave absorber at lower frequency range using heterogeneous morphology of developed materials is also presented. The proposed microwave absorbing materials can be potentially utilized for the shielding applications. [Display omitted] • Study explores the impact of morphology on microwave absorption in heterogeneous mixtures. • Milled Carbonyl iron and its mixture exhibit absorption in lower frequency regions. • E-waste-based mixtures with complex morphology exhibit absorption in higher frequency regions. • Multilayering techniques extend bandwidth, with a three-layer absorber designed using genetic algorithms. • Wideband absorption (11.62 GHz) achieved in the lower frequency range (0.5–12.12 GHz) at a compact (<2 mm) thickness. [ABSTRACT FROM AUTHOR]