Electromagnetic characterization and shielding effectiveness of concrete composite reinforced with carbon nanotubes in the mobile phones frequency band

The dielectric properties of high‐temperature stable single‐source precursor‐derived SiC/HfCxN1−x/C ceramic nanocomposites are determined by microwave absorption in the X‐band (8.2–12.4 GHz) at room temperature. The samples synthesized at 1700°C, denoted as SiC/5HfCxN1−x/C‐1700°C and SiC/15HfCxN1−x/C‐1700°C ceramics, comprising ≈ 1.3 and ≈ 4.2 vol% HfCxN1−x, respectively, show enhanced microwave absorption capability superior to hafnium‐free SiC/C‐1700°C. The minimum reflection loss of SiC/5HfCxN1−x/C‐1700°C and SiC/15HfCxN1−x/C‐1700°C are −47 and −32 dB, and the effective absorption bandwidth amount to 3.1 and 3.6 GHz, respectively. Segregated carbon, including graphitic carbon homogeneously dispersed in the SiC matrix and less ordered carbon deposited as a thin film on HfCxN1−x nanoparticles, accounts for the unique dielectric behavior of the SiC/HfCxN1−x/C ceramics. Due to their large reflection loss and their high chemical and temperature stability, SiC/5HfCxN1−x/C‐1700°C and SiC/15HfCxN1−x/C‐1700°C ceramics are promising candidate materials for electromagnetic interference applications in harsh environment.

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“…Eq. reduces then to:

{normalε}^{″} \approx \frac{normalσ}{2 π f {normalε}_{0}}

Accordingly, an increase/decrease in ε′′ can be directly attributed to the increase/decrease in the electrical conductivity (σ).…”

Section: Resultsmentioning

confidence: 99%

Microwave Absorption of SiC/HfC_xN_1−x/C Ceramic Nanocomposites with HfC_xN_1−x‐Carbon Core–Shell Particles

Wen

Feng

et al. 2016

J. Am. Ceram. Soc.

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“…5d). 1,4,5,11,13,19,20,28,31,32,[35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] This nding is noteworthy because the LG-4 lm would satisfy several commercial requirements for an EMI shielding material, for example ultrahigh EMI SE (73.7 dB), low density (2.05 g cm À3 ), ultrathin thickness (0.014 mm), anti-corrosion, high exibility and easy fabrication.…”

Section: Morphologies Of Graphene Lmsmentioning

confidence: 99%

Ultrathin flexible graphene films with high thermal conductivity and excellent EMI shielding performance using large-sized graphene oxide flakes

Lin

Zhang

et al. 2019

RSC Adv.

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“…There is a growing interest in the electromagnetic radiation shielding and radar absorbing materials (RAM) areas due to the intense growth of high-performance electrical and electronic systems in commercial, military, and scientific fields [1]. As a result, the search for new materials with lower cost, lower weight, and ease of processing has increased [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…RAM can be obtained from different materials, as long as they favor losses of the incident energy in the frequency range of microwaves. For example, any ferrites, carbon black, carbon nanotubes (CNT), and conducting polymers can be cited [3][4][5][6][7]. In this area, the conducting polymers have attracted significant attention due to the lower density in relation to ferrites and carbonyl iron, for example, and good electrical conductivity values.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic, Morphological, and Electrical Characterization of POMA/Carbon Nanotubes-Based Composites

Pinto

Rezende

2017

Journal of Nanomaterials

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This study involves the preparation of conducting composites based on poly(o-methoxyaniline) (POMA) and carbon nanotubes (CNT) and the evaluation of them as radar absorbing materials (RAM), in the frequency range of 8.2–12.4 GHz (X-band). The composites were obtained by synthesis in situ of POMA in the presence of CNT (0.1 and 0.5 wt% in relation to the o-methoxyaniline monomer). The resulting samples—POMA/CNT-0.1 wt% and POMA/CNT-0.5 wt%—were incorporated in an epoxy resin matrix in the proportion of 1 and 10 wt%. FT-IR analyses show that the POMA was successfully synthesized on the CNT surface. SEM analyses show that the synthesized POMA recovered all CNT surface. Electrical conductivity measurements show that the CNT contributed to increase the conductivity of POMA/CNT composites (1.5–6.7 S·cm−1) in relation to the neat POMA (5.4 × 10−1 S·cm−1). The electromagnetic characterization involved the measurements of complex parameters of electrical permittivity (ε) and magnetic permeability (µ), using a waveguide in the X-band. From these experimental data reflection loss (RL) simulations were performed for specimens with different thicknesses. The complex parameters show that the CNT in the composites increased ε and µ. These results are attributed to the CNT network formation into the composites. Simulated RL curves of neat POMA and POMA/CNT in epoxy resin show the preponderant influence of POMA on all RL curves. This behavior is attributed to the efficient CNT recovering by POMA. RL results show that the composite based on 10 wt% of POMA/CNT-0.5 wt% in epoxy resin (9 mm thickness) presents the best RL results (≈87% of attenuation at 12.4 GHz).

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Electromagnetic characterization and shielding effectiveness of concrete composite reinforced with carbon nanotubes in the mobile phones frequency band

Cited by 113 publications

References 37 publications

Microwave Absorption of SiC/HfC_xN_1−x/C Ceramic Nanocomposites with HfC_xN_1−x‐Carbon Core–Shell Particles

Microwave Absorption of SiC/HfC_xN_1−x/C Ceramic Nanocomposites with HfC_xN_1−x‐Carbon Core–Shell Particles

Ultrathin flexible graphene films with high thermal conductivity and excellent EMI shielding performance using large-sized graphene oxide flakes

Electromagnetic, Morphological, and Electrical Characterization of POMA/Carbon Nanotubes-Based Composites

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Electromagnetic characterization and shielding effectiveness of concrete composite reinforced with carbon nanotubes in the mobile phones frequency band

Cited by 113 publications

References 37 publications

Microwave Absorption of SiC/HfCxN1−x/C Ceramic Nanocomposites with HfCxN1−x‐Carbon Core–Shell Particles

Microwave Absorption of SiC/HfCxN1−x/C Ceramic Nanocomposites with HfCxN1−x‐Carbon Core–Shell Particles

Ultrathin flexible graphene films with high thermal conductivity and excellent EMI shielding performance using large-sized graphene oxide flakes

Electromagnetic, Morphological, and Electrical Characterization of POMA/Carbon Nanotubes-Based Composites

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Product

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Microwave Absorption of SiC/HfC_xN_1−x/C Ceramic Nanocomposites with HfC_xN_1−x‐Carbon Core–Shell Particles

Microwave Absorption of SiC/HfC_xN_1−x/C Ceramic Nanocomposites with HfC_xN_1−x‐Carbon Core–Shell Particles