The effects of temperature and frequency on the dielectric properties, electromagnetic interference shielding and microwave-absorption of short carbon fiber/silica composites

Cao, Mao‐Sheng; Song, Wei‐Li; Hou, Zhi‐Ling; Wen, Bo; Yuan, Jie

doi:10.1016/j.carbon.2009.10.028

Cited by 1,714 publications

(684 citation statements)

References 39 publications

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“…The broadening of the peak shows the spread of the relaxation with a relaxation time constant distribution. Furthermore, the appearance of peaks in M  provides a clear indication of the real dielectric relaxation process [32][33][34][35][36]. Figure 8 shows the complex modulus plots ( M  versus M  ) at various SM T .…”

Section: Electric Modulus Analysismentioning

confidence: 99%

Complex impedance and electric modulus studies of magnetic ceramic Ni0.27Cu0.10Zn0.63Fe2O4

2015

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Abstract:The electrical properties of Ni 0.27 Cu 0.10 Zn 0.63 Fe 2 O 4 (NCZF) prepared from auto combustion synthesis of ferrite powders have been studied by impedance and modulus spectroscopy. We studied frequency and temperature dependencies of impedance and electric modulus of NCZF in a wide frequency range (20 Hz-5 MHz) at different measuring temperatures SM T (30-225 ℃). The complex impedance spectra clearly showed both grain and grain boundary effects on the electrical properties. The observed impedance spectra indicated that the magnitude of grain boundary resistance gb R becomes more prominent compared to grain resistance b R at room temperature, and with the increase in SM T , gb R decreases faster than the intrinsic b R . The frequency response of the imaginary part of impedance showed relaxation behavior at every SM T , and the relaxation frequency variation with SM T appeared to be of Arrhenius nature and the activation energy has been estimated to be 0.37 eV. A complex modulus spectrum was used to understand the mechanism of the electrical transport process, which indicated that a non-Debye type of conductivity relaxation characterizes this material.

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Section: Electric Modulus Analysismentioning

confidence: 99%

Complex impedance and electric modulus studies of magnetic ceramic Ni0.27Cu0.10Zn0.63Fe2O4

2015

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“…The simplest way to obtain dispersive materials is to use the conductive inclusions inside the composite [17][18][19]. Typically, composites with conductive filler above percolation threshold have pronounced ε ∼ 1/ω dispersion in microwave frequency range.…”

Section: The Advantage Of Using Dispersive Materialsmentioning

confidence: 99%

Design of Carbon Nanotube-Based Broadband Radar Absorber for Ka-Band Frequency Range

Bychanok¹,

Gorokhov²,

Meisak³

et al. 2017

PIER M

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Abstract-The general principles of design and development of microwave absorbing materials are discussed and analysed in respect to 26-37 GHz frequency range (Ka-band). Dispersive composite materials based on carbon nanotubes in epoxy resin matrix are produced, and their electromagnetic responses are investigated in Ka-band. Both theoretical and experimental results demonstrate that presented composites may be used as compact effective absorbers in 26-37 GHz range.

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“…1,2 On the other hand, ceramics, ferrites, metallic magnets, CNTs and their hybrids are widely utilized as conducting fillers into polymer matrix to achieve high electrical conducting composites for efficient EMI shielding application. [3][4][5][6][7][8] Cao et al reported the composite loading with 6 vol.% CdS-MWCNTs shows the best absorption of -47 dB at 473 K with a thickness of 2.6 mm in the temperature range of 323-573 K and X band. 6 CNT/Silica composite loading with 10 wt% MWCNTs can show EMI SE of ∼ 24.5 dB in X-band at temperature range from 100 to 500 • C. 7 Further, carbon fiber/silica composites can show shielding effectiveness greater than 10 dB in X-band region.…”

Section: Introductionmentioning

confidence: 99%

“…6 CNT/Silica composite loading with 10 wt% MWCNTs can show EMI SE of ∼ 24.5 dB in X-band at temperature range from 100 to 500 • C. 7 Further, carbon fiber/silica composites can show shielding effectiveness greater than 10 dB in X-band region. 8 Despite good EMI shielding performance in some cases, their drawbacks are high loading content, thickness, high density and poor stability, which severely hinder their applications.…”

Section: Introductionmentioning

confidence: 99%

An asymmetric electrically conducting self-aligned graphene/polymer composite thin film for efficient electromagnetic interference shielding

Kumar

Cho

et al. 2017

AIP Advances

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Here, we study the self-aligned asymmetric electrically conductive composite thin film prepared via casting of graphene oxide (GO)/poly (vinylidene-hexafluoropropylene) (PVDF-HFP) dispersion, followed by low temperature hydriodic acid reduction. The results showed that composite thin film revealed the high orientation of graphene sheets along the direction of film surface. However, graphene sheets are asymmetrically distributed along the film thickness direction in the composite film. Both sides of as prepared composite film showed different surface characteristics. The asymmetric surface properties of composite film induced distinction of surface resistivity response; top surface resistivity (21 Ohm) is ∼ 4 times higher than bottom surface resistivity (5 Ohm). This asymmetric highly electrically conducting composite film revealed efficient electromagnetic interference (EMI) shielding effectiveness of ∼ 30 dB. This study could be crucial for achieving aligned asymmetric composite thin film for high-performance EMI shielding radiation.

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The effects of temperature and frequency on the dielectric properties, electromagnetic interference shielding and microwave-absorption of short carbon fiber/silica composites

Cited by 1,714 publications

References 39 publications

Complex impedance and electric modulus studies of magnetic ceramic Ni0.27Cu0.10Zn0.63Fe2O4

Complex impedance and electric modulus studies of magnetic ceramic Ni0.27Cu0.10Zn0.63Fe2O4

Design of Carbon Nanotube-Based Broadband Radar Absorber for Ka-Band Frequency Range

An asymmetric electrically conducting self-aligned graphene/polymer composite thin film for efficient electromagnetic interference shielding

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