Optimizing electromagnetic parameters to enhance the microwave absorbing properties of core–shell FeCo2O4@flaky FeSiAl composites

Abstract

The high complex permittivity of flaky FeSiAl in microwave-absorbing materials leads to poor electromagnetic impedance matching and a narrow effective absorption bandwidth. To overcome this issue, we developed a novel approach by wrapping magnetic FeCo2O4 on the surface of flaky FeSiAl using a hydrothermal method, followed by calcination. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were used to confirm the formation of a FeCo2O4@flaky FeSiAl composite with a well-defined core–shell microstructure. The prepared FeCo2O4@flaky FeSiAl composite exhibited a significantly reduced complex permittivity, which improved its electromagnetic impedance matching performance. When filled in paraffin with a thickness of only 1.6 mm, the composite demonstrated excellent electromagnetic wave absorption performance, with an effective absorption bandwidth of 5.60 GHz (RL < − 10 dB), indicating its potential in the field of microwave-absorbing materials. These results were achieved owing to the unique properties of the FeCo2O4@flaky FeSiAl composite, demonstrating its potential as a high-performance microwave absorber. This study may be of significant interest to researchers and engineers in the fields of magnetism and magnetic materials, especially those in the microwave field.