Strategic dual-stratum microwire composites for effective electromagnetic shielding with low microwave reflectivity

Abstract

The dynamic potential of ferromagnetic microwire composites, which are traditionally responsive to magnetic fields, stress, or hybridization, is explored for enhanced electromagnetic (EM) shielding in lightweight materials, targeting applications like microwave electronics, structural health monitoring, and temperature sensing. This study presents a novel dual-stratum design combining as-cast and annealed wire arrays (i.e., A+X), where X represents any annealed arrays achieving high shielding. Integrating amorphous Co₆₀Fe₁₅B₁₅Si₁₀ wires with crystalline counterparts balances impedance matching, improves absorption efficiency, and induces polarization effects via wire array topologies. Transmission electron microscopy (TEM) revealed nanocrystallites formed within an amorphous matrix, significantly boosting total shielding effectiveness (SE_T) to ~28 dB (98.4% attenuation) at only 0.026 vol% filler loading. The enhancement stems from synergistic interactions between as-cast and crystalline microwires acting as electrical and magnetic dipoles, optimizing EM wave interaction through combined dielectric and magnetic responses. Comparative analyses show thermal annealing is more suitable than Joule annealing for large-scale production. This cost-effective approach produces lightweight composites with superior SE_T, simple structure, and multifunctionality. These advancements expand multifunctional composite applications across industries, enabling effective microwave cloaking, non-contact stress monitoring, and thermal management with minimal filler content and complexity.