Enhanced Low‐Frequency Microwave Absorption and Corrosion Resistance of FeSiAl Using Low‐Melting‐Point Glass Phase Coatings

ABSTRACT This study developed a FeSiAl@LMPGP composite material to address the demand for low‐frequency electromagnetic absorption. Through controllable heat treatment, FeSiAl particles and PbO nanoparticles self‐assembled into a high‐density Mott–Schottky heterointerface structure, which exhibited a significant built‐in electric field (BIEF) effect. Experimental and theoretical analyses revealed that this structure synergistically enhanced magnetic medium coupling and impedance matching by blocking conductive channels between FeSiAl particles via a dense PbO coating, thereby improving impedance matching. This sample achieved 86% effective coverage in the P band within the frequency range of 0.4–1.1 GHz. Its maximum effective absorption bandwidth (EAB max ) spanned from 1.4 to 4.2 GHz, providing an 86.7% coverage rate for both the L band and S band (EAB 1 , RL ≤ −5 dB). Furthermore, the corrosion current was reduced from 2.66 × 10 −5 A to 6.58 × 10 −6 A, significantly enhancing corrosion resistance. This improvement in intrinsic corrosion resistance was attributed to the regulation of interfacial charge distribution, enhanced polarization, and the formation of a passivation layer facilitated by the Mott–Schottky heterointerface, effectively suppressing corrosion. Theoretical simulations confirmed that PbO‐mediated charge redistribution coordinated the dielectric constant and magnetic permeability parameters, thereby optimizing impedance matching. This research provides critical theoretical and experimental insights for designing low‐frequency electromagnetic absorption materials.