Optimized microstructure and impedance matching for improving the absorbing properties of core-shell C@Fe3C/Fe nanocomposites

The carbon coated core-shell C@Fe3C/Fe nanocomposites were prepared by plasma arc-discharging method. The core-shell and graphite network structures were obtained, which could improve the absorbing properties by optimizing the impedance matching and increase the internal reflections of the propagated microwave. By varying the coating thickness from 1.0 to 5.0 mm, the reflectivity of C@Fe3C/Fe nanocomposites prepared in 30% CH4 is less than -20 dB nearly in the whole range of 2-18 GHz. The minimum reflection loss value reaches -32.9 dB at 14.2 GHz and the effective bandwidth (<-10 dB) is from 12.1 to 17.2 GHz (d = 1.7 mm). The obtained network structured core-shell C@Fe3C/Fe absorber would be an attractive candidate for microwave absorbing materials for its low density, strong absorption, and broad bandwidth. (C) 2018 Elsevier B.V. All rights reserved.