Constructing multi-interface-structured FeNi/Fe2O3@Al2O3@C rod-like nanocomposites for superior microwave-absorption performance

Abstract

Constructing multi-interfaces is an effective strategy for realizing thin, wide, strong, and stable microwave absorbers. In this work, FeNi/Fe2O3@Al2O3@C nanocomposites have been prepared; in their microstructure, FeNi nanoparticles with a diameter of ∼20 nm and Fe2O3 nanoparticles with a size of ∼5 nm are dispersed in an Al2O3 µm scale rod covered by a carbon layer, in which the multi-interfaces of FeNi–Al2O3, FeNi–Fe2O3, Fe2O3–Al2O3, and Al2O3–C are constructed. Proper impedance matching, quarter-wavelength interference cancellation, and integrated electromagnetic (EM) loss capacity can be realized through optimization of the EM parameters accompanied with a multi-interface structure, resulting in good microwave-absorption behaviors with the merits of being broad, strong, thin, and stable. The nanocomposites have −49.6 dB of minimal reflection loss (RLm) at 3.2 mm 5.44 GHz (12.56–18 GHz) of effective absorption bandwidth at 2.1 mm and a RLm exceeding −10 dB at 1.6–10 mm and −20 dB at 1.8–10 mm. These results demonstrate that constructing multi-interfaces plays a guiding role in obtaining superior microwave absorbers.