Fe/amorphous ceramics core/shell structured nanoflakes-assembled rod-like architecture for efficient microwave absorber

Abstract

A rod-like architecture self-assembled from Fe/amorphous ceramics core/shell structured nanoflakes has been prepared by arc discharging steelmaking slag in an Ar/H2 atmosphere, in which the amorphous ceramic shell is composed of MgO, Al2O3, MgSiO3 and CaSiO3. The electromagnetic absorbing performance of the rod-like architecture is evaluated over the range of 2–18 GHz. Multiple dielectric relaxation of the permittivity is attributed to the size distribution and novel morphology of the rod-like architecture. The experimental permeability is in good agreement with the calculated curves based on the Landau–Lifshitz–Gilbert equation. The magnetic loss ability is superior to the dielectric loss ability, due to the planar anisotropy of flake-shaped particles. At a thickness of 2.4 mm, the minimal reflection loss (RL) can reach −35.04 dB at 10.96 GHz. In particular, the effective bandwidth with RL exceeding −10 dB remains at least 2.56 GHz at a thickness of 1.6–4.1 mm, and exhibits a red shift phenomenon as layer thickness increases. Such efficient EM absorption performances originate from magnetic/dielectric loss ability accompanied by 1/4-wave elimination. The represented work not only provides a good reference for efficient microwave absorption, but also broadens the application of steelmaking slag.