Synthesis and enhanced microwave absorption properties of Ni@Ni₂O₃ core-shell particles

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• 作者：Bochong Wang ; Junli Zhang ; Tao Wang ; Liang Qiao ; Fashen Li ; ^{lifs@lzu.edu.cn}
• 关键词：Ni@Ni2O3 core&ndash ; shell particles ; Hydrogen peroxide ; Permittivity ; Permeability ; Microwave absorption ; Quarter-wavelength matching model
• 刊名：Journal of Alloys and Compounds
• 出版年：2013
• 出版时间：5 August, 2013
• 年：2013
• 卷：567
• 期：Complete
• 页码：21-25
• 全文大小：1898 K

文摘

In this paper, we reported on the enhanced microwave absorbing properties of the Ni@Ni₂O₃ core-shell soft magnetic particles which were synthesized by a simple hydrogen peroxide oxidation method. The chemical state and the morphology of the Ni@Ni₂O₃ particle surface were analyzed by X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM), respectively. Complex electromagnetic parameters (permittivity and permeability) of the paraffin mixed composite were measured in the frequency range of 0.1-18 GHz. Compared with the uncoated Ni/paraffin composite, the permittivity of Ni@Ni₂O₃/paraffin composite decreased dramatically. The reflection loss (RL) of the composite exceeding ?20 dB in the frequency range of 4.0-12.6 GHz were obtained for the absorber thicknesses of 1.8-4.3 mm, while an optimal RL of ?53.5 dB was achieved at 7.9 GHz for the thickness of 2.5 mm. The good microwave absorption properties resulted from a proper impedance match as a consequence of the insulator Ni₂O₃ shell around Ni particles. Quantitative calculation demonstrated that not only the RL peak position but also the number of the peaks were determined by the quarter-wavelength matching model.