Synthesis of hierarchical dendritic micro-nano structure CoxFe1−x alloy with tunable electromagnetic absorption performance
- 14 August 2013
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of Materials Chemistry A
- Vol. 1 (40), 12462-12470
- https://doi.org/10.1039/c3ta12840g
Abstract
In this paper, both the leaf-like dendritic CoxFe1−x (x = 0.1, 0.3, 0.5 and 0.7) alloys and novel grain-like dendritic nanostructure Co0.9Fe0.1 alloy and ε-Co were synthesized by an electric field-induced and electrochemical reduction method under over-polarization current. The formation of these two dendritic structures is not only attributed to the electric-field strength and ion concentration gradient, but also related to their crystalline structure. The trunks and branches of leaf-like dendritic bcc CoxFe1−x grow along three of the six equivalent directions. However, for grain-like dendritic hcp ε-Co, their six branches grow along the six equivalent directions, and the trunks are oriented preferably along [0002] direction. The electromagnetic absorption (EMA) performance of leaf-like structure CoxFe1−x alloys are obviously enhanced with Co content increase from −21.7 dB for Co0.1Fe0.9 to −59.1 dB for Co0.5Fe0.5. Meanwhile, the response frequency of maximum reflection loss (RL) shifts to the higher band. In the case of grain-like dendritic Co0.9Fe0.1 alloy, it has the widest frequency band from 5 to 18 GHz with RL < −20 dB due to the mixed phase composition. We ascribe the enhancement of dendritic CoxFe1−x alloys' EMA performance to the different elemental compositions, crystalline structures, surface anisotropy and crystal defects, which contribute to enhancing the effective complementarities between dielectric loss and magnetic loss.This publication has 38 references indexed in Scilit:
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