Morphology modulation induced enhancement of microwave absorption performance in Fe20Ni80 particles

Exploring the influence of material morphology on microwave absorption performance is of significance for designing high performance absorbers. A feasible coprecipitation strategy was proposed for preparing three kinds of Fe20Ni80 particles with different morphologies (ball-like, worm-like and flower-like). The mor-phology, structure and performance of the particles were contrastively studied. The results showed that the morphology had a remarkable effect on microwave absorption performance. Under the same structure and composition, the performance of worm-like particles was obviously better than that of other particles. Particularly, under the filler loading of 20 wt%, the minimum reflection loss (RLmin) value reached - 48.5 dB at 7.9 GHz, and the maximum effective absorption bandwidth (EABmax) was 4.3 GHz (8.3-12.6 GHz) with a matching thickness of 2.5 mm. The arrangement of worm-like particle resembles a chaotic porous nest, which optimizes impedance matching. In addition, the worm-like particle has a large aspect ratio, ex-hibiting stronger dielectric loss ability. The loss mechanisms to incident waves mainly include conductive loss, interfacial polarization loss, natural resonance and exchange resonance.(c) 2022 Published by Elsevier B.V.