Influence of a graphite shell on the thermal, magnetic and electromagnetic characteristics of Fe nanoparticles

Xianguo Liu, Siu Wing Or, Yuping Sun, Weihuo Li, Yizhu He, Guohui Zhu, Chuangui Jin, Qun Yan, Yaohui Lv, Siu Lau Ho, Shengsheng Zhao

Research output: Journal article publicationJournal articleAcademic researchpeer-review

30 Citations (Scopus)

Abstract

Graphite-coated Fe nanocapsules were prepared by arc discharge method. Fe nanocapsules have a core/shell microstructure, in which Fe nanoparticles as cores and graphite layers as shells. Compared with Fe nanoparticles with an oxide shell, the graphite shell can restrain the growth of Fe nanoparticles, which leads to lower saturation magnetization and higher natural resonance frequency. The Fe nanocapsules are stable securely below 220 °C in the air, due to the enhancement of thermal stability and the anti-oxidation by graphite layer shell. Dielectric relaxation of graphite shell and the interfacial relaxation between graphite shell and Fe core lead to the dual nonlinear dielectric resonance. Graphite shells can dramatically improve the magnetic/dielectric loss and the attenuation constant in the 2-18 GHz though the dual dielectric resonance and protection of Fe cores, leading to enhanced microwave absorption properties of Fe nanocapsules at 2-18 GHz.
Original languageEnglish
Pages (from-to)239-244
Number of pages6
JournalJournal of Alloys and Compounds
Volume548
DOIs
Publication statusPublished - 25 Jan 2013

Keywords

  • Complex permeability
  • Complex permittivity
  • Graphite
  • Magnetic
  • Nanoparticles

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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