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

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/H-2 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.