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Date of Publication:2016-01-01

Journal:材料导报

Issue:12

Page Number:31-36

ISSN No.:1005-023X

Abstract:The carbon-coated nickel nanocapsules (Ni(C) NCs) were prepared by DC arc-discharge method in CH4atmosphere and mixed as electromagnetic absorber under various mass percentages(10%,20%,30% and 40%)with paraffin matrix to form composite wave absorbing materials, whose relative complex permeabilities and complex permittivities were measured within the frequency range of 0.1-18 GHz in order to investigate the electromagnetic characteristics and absorption mechanism of such Ni(C) nanocapsules/paraffin composites. The results revealed that Ni(C) nanocapsules exhibited significant characteristics of polarization losses and its dielectric constant drastically attenuated with increasing frequency in the low frequency range, while the magnetic permeability showed a broaden width with multiple resonance peaks. The increment of Ni (C) nanocapsules' mass fraction caused the gradual rise of dielectric constant, and meanwhile, rises of real and imaginary parts of complex permeability in the frequency range of 0.1-8 GHz and 0.1-10 GHz, respectively. However, in the frequency range of 8-18 GHz and 10-18 GHz, the real part reduced and imaginary part changed at an almost constant rate. We observed that electromagnetic loss of Ni(C) nanocapsules is mainly dominated by dielectric loss, and theoretically analyzed in detail thepolarization, eddy current and electromagnetic wave reflection, as well as the related mechanisms. © 2016, Materials Review Magazine. All right reserved.

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