Excellent electrically insulated, thermal-oxidation resistant and corrosion resistant flaky-FeSiAl/BN core–shell composites for high-performance microwave absorption in harsh environments

Abstract

Currently, multifunctional microwave absorption (MA) materials have become increasingly important in addressing the serious issue of electromagnetic pollution. In this study, flaky FeSiAl (FFSA)/hexagonal boron nitride (h-BN) composites with a core–shell structure were prepared by plasma-assisted ball milling. The FFSA9BN1 composite, with a mass ratio of 9:1 (FFSA:h-BN), exhibits a minimum reflection loss (RLmin) of −68.18 dB at a thickness of 2.14 mm, because the h-BN shells improve the impedance matching of the composites and produce abundant polarization loss. Additionally, the MA performance of the composites hardly shows a decline even after a thermal oxidation at 500 °C for 12 h due to the dense h-BN shells as oxygen barriers. Simultaneously, the corrosion rate of the FFSA/h-BN composites is 66.5% less than that of the FeSiAl cores. Consequently, plasma-assisted ball milling provides a facile and eco-friendly technology to prepare multifunctional FFSA/h-BN core–shell composites for diverse applications in some extreme environments.