层状FeSiBCr引入纳米晶/非晶异质结构实现同步增强吸收、拓宽吸收带宽并降低匹配厚度OA

Synchronously enhancing absorption ability,expanding absorption bandwidth,and reducing matching thickness still pose significant challenges for a single material.In this work,laminated powders were prepared by vertically milling amorphous FeSiBCr powder.Due to the high energy during milling process,～15 nm α-Fe phase and～3 nm surface oxidation layer appeared in laminated FeSiBCr,which created multiple dielectric relaxation,magnetic-dielectric interface and planar anisotropy.Multiple dielectric relaxation originating from crystalline/amorphous heterostructures and oxide layer contributed to low permittivity and enhanced dielectric loss capacity,planar anisotropy induced by flaky morphology and α-Fe phase improved permeability and magnetic loss ability.Low permittivity and high permeability facilitated impedance matching.Enhanced loss capability and good impedance matching resulted in good absorption performances.Compared with that(RLm of-8.99 dB at 2.6 mm and EAB of 0 GHz)of FeSiBCr flakes,the laminated FeSiBCr exhibited an effective absorption bandwidth(EAB)of 6.56 GHz at 1.8 mm thickness and the minimal reflection loss(RLm)of-34.22 dB at 2.0 mm.Moreover,the periodic gradient structure excited resonance at different frequencies to form multiple resonance superposition,thus expanding EAB to 13.18 GHz with an increase of up to 200.9%.This work offers a new approach for the rational design of laminated amorphous materials with crystalline/amorphous heterostructures for efficient microwave absorbers.