scholarly journals NiS2@rGO Nanosheet Wrapped with PPy Aerogel: A Sandwich-Like Structured Composite for Excellent Microwave Absorption

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 833 ◽  
Author(s):  
Zhi Zhang ◽  
Qi Lv ◽  
Yiwang Chen ◽  
Haitao Yu ◽  
Hui Liu ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
In Situ Polymerization ◽  
Impedance Matching ◽  
Interfacial Polarization ◽  
The Novel ◽  
Step Method ◽  
Absorption Bands ◽  
Absorption Performance ◽  
Electromagnetic Pollution

To reduce electromagnetic pollution as well as increase the accuracy of high-precision electronic equipment, more attention has been paid to new electromagnetic wave (EMW) absorbing materials, which have the advantages of strong absorption, wide absorption bands, and a narrow thickness. In this study, a novel ternary type of the NiS2@rGO/polypyrrole (PPy) sandwich-like structured composites was synthesized via a facile two-step method, in which the hydrothermal method was used to prepare NiS2@rGO binary composites and then the in situ polymerization method was used to synthesize the PPy, which acted as the outer layer of the sandwich-like structure. The morphologies and electromagnetic absorption performance of the NiS2@rGO/PPy were measured and investigated. A sample with 6 wt% NiS2@rGO/PPy loading paraffin-composite obtained an outstanding reflection loss (RL) of −58.7 dB at 16.44 GHz under a thickness of 2.03 mm. Simultaneously, the effective electromagnetic wave absorption bandwidth for RL < −10 dB, which covered 7.04 to 18.00 GHz (10.96 GHz), was achieved by changing the thickness of the absorber from 2.0 to 3.5 mm. The results not only suggest that the NiS2@rGO/PPy composite has excellent performance in the field of EMW absorption but also prove that the novel sandwich-like structure can contribute to appropriate impedance matching through multiple relaxation and interfacial polarization processes.

scholarly journals Polypyrrole Chains Decorated on CoS Spheres: A Core-Shell Like Heterostructure for High-Performance Microwave Absorption

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 166 ◽  
Author(s):  
Hui Liu ◽  
Guangzhen Cui ◽  
Ling Li ◽  
Zhi Zhang ◽  
Xuliang Lv ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
High Performance ◽  
In Situ Polymerization ◽  
Impedance Matching ◽  
Synthesis Method ◽  
Interfacial Polarization ◽  
Cobalt Sulfide ◽  
Core Shell ◽  
Loss Mechanism

Cobalt sulfide composites have exhibited great potential in terms of microwave absorption, owing to their low price, relatively high capacitance, and excellent electrocatalytic activity. Thus, a novel core-shell like structure comprising cobalt sulfide@polypyrrole (CoS@PPy) composite was synthesized by a facile solvothermal synthesis method and in situ polymerization. When coated by the heterostructure polypyrrole aerogel, CoS@PPy composite exhibited excellent microwave absorption properties with an optimal reflection loss (RL) of −41.8 dB at 6.96 GHz. Furthermore, the absorption bandwidth (RL < −10 dB) of 5.4 GHz could be reached at a coating thickness of 2.05 mm, probably attributing to the synergistic effect of good impedance matching, interfacial polarization, dipole polarization, and conductivity loss. Moreover, this work proposed a loss mechanism mode which probably occurred in the CoS@PPy composites. It was demonstrated that the CoS@PPy composite is a promising material in the field of electromagnetic wave absorption.

Construction and Microwave Absorption Properties of Core@Double-Shell Structured Fe3O4@Polyaniline@MnO2 Nanospheres

NANO ◽  
2020 ◽  
Vol 15 (03) ◽  
pp. 2050032 ◽  
Author(s):  
Wentong Yang ◽  
Xiansen Yang ◽  
Xiang Li ◽  
Md. Zahidul Islam ◽  
Yubing Dong ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
In Situ Polymerization ◽  
Impedance Matching ◽  
Multiple Reflections ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
The Core ◽  
Absorption Performance ◽  
Minimum Reflection Loss

In this paper, we designed a core@double-shell nanostructure to enhance the electromagnetic wave absorption performance of hybrid nanospheres. Herein, the core@double-shell structured Fe3O4@polyaniline@MnO2 nanospheres were successfully prepared by a facile solvothermal process and in situ polymerization methods. The morphology, structure, magnetism and microwave absorption properties were studied. The results reveal that the FPM nanospheres exhibit extraordinary microwave absorbing performance compared to those of either Fe3O4 or Fe3O4@polyaniline nanospheres. The minimum reflection loss of the FPM nanospheres is [Formula: see text]14.7[Formula: see text]dB at 15.76[Formula: see text]GHz with the thickness of 3.5[Formula: see text]mm, and the corresponding effective absorption bandwidth can reach 4.75[Formula: see text]GHz. The perfect EMW absorption of nanospheres can be ascribed to multi-interface polarization, multiple reflections and good impedance matching originated from the core@double-shell nanostructure.

scholarly journals Tuning Dielectric Loss of SiO2@CNTs for Electromagnetic Wave Absorption

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2636
Author(s):  
Fenghui Cao ◽  
Jia Xu ◽  
Xinci Zhang ◽  
Bei Li ◽  
Xiao Zhang ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
High Performance ◽  
Low Cost ◽  
Impedance Matching ◽  
3D Structure ◽  
Carbon Matrix ◽  
Current Approach ◽  
Matrix Composites ◽  
Simple Method ◽  
Absorption Performance

We developed a simple method to fabricate SiO2-sphere-supported N-doped CNTs (NCNTs) for electromagnetic wave (EMW) absorption. EMW absorption was tuned by adsorption of the organic agent on the precursor of the catalysts. The experimental results show that the conductivity loss and polarization loss of the sample are improved. Meanwhile, the impedance matching characteristics can also be adjusted. When the matching thickness was only 1.5 mm, the optimal 3D structure shows excellent EMW absorption performance, which is better than most magnetic carbon matrix composites. Our current approach opens up an effective way to develop low-cost, high-performance EMW absorbers.

scholarly journals Preparation and Conductive and Electromagnetic Properties of Fe3O4/PANI Nanocomposite via Reverse In Situ Polymerization

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Di Zhang ◽  
Huaiyin Chen ◽  
Ruoyu Hong
Keyword(s):  
In Situ Polymerization ◽  
Rapid Development ◽  
Chloroform Solution ◽  
Electromagnetic Properties ◽  
Network Analyzer ◽  
The Novel ◽  
Electromagnetic Devices ◽  
Ft Ir ◽  
Polymerization Method

In this paper, the magnetite/polyaniline (PANI) nanocomposite was prepared by the novel reverse in situ polymerization method. Fe3O4 magnetic nanoparticles were synthesized in situ in PANI chloroform solution to form a suspension containing the Fe3O4/PANI nanocomposite. It overcame the disadvantage of oxidation of the Fe3O4 by the oxidant in conventional method. The Fe3O4/PANI chloroform suspension and the Fe3O4/PANI powder were characterized by FT-IR, TEM, XRD, vibrating sample magnetometer, Gouy magnetic balance, conductivity meter, and vector network analyzer. It is demonstrated that the Fe3O4/PANI suspension has a good electrical conductivity that is up to 2.135 μS/cm at the optimal ratio of reactants. The Fe3O4 nanoparticles are well dispersed in the PANI network with a particle size of about 10 nm. Fe3O4/PANI powder has high saturation magnetization and magnetic susceptibility, as well as a broad application prospect in the field of electromagnetic devices. The Fe3O4/PANI powder exhibits an excellent microwave absorption behavior, which can be an outstanding candidate for the rapid development of broadband shielding materials.

scholarly journals Electromagnetic Wave Absorption Properties of Structural Conductive ABS Fabricated by Fused Deposition Modeling

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1217 ◽  
Author(s):  
Wenwen Lai ◽  
Yan Wang ◽  
Junkun He
Keyword(s):  
Electromagnetic Wave ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Analysis Method ◽  
Absorption Bands ◽  
Absorption Properties ◽  
Theoretical Simulation ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Absorption Performance

To obtain excellent electromagnetic wave (EMW) absorption materials, the design of microstructures has been considered as an effective method to adjust EMW absorption performance. Owing to its inherent capability of effectively fabricating materials with complex various structures, three-dimensional (3D) printing technology has been regarded as a powerful tool to design EMW absorbers with plentiful microstructures for the adjustment of EMW absorption performance. In this work, five samples with various microstructures were prepared via fused deposition modeling (FDM). An analysis method combining theoretical simulation calculations with experimental measurements was adopted to investigate EMW absorbing properties of all samples. The wood-pile-structural sample possessed wider effective absorption bandwidth (EAB; reflection loss (RL) < − 10 dB, for over 90% microwave absorption) of 5.43 GHz and generated more absorption bands (C-band and Ku-band) as compared to the honeycomb-structural sample at the same thickness. Designing various microstructures via FDM proved to be a convenient and feasible method to fabricate absorbers with tunable EMW absorption properties, which provides a novel path for the preparation of EMW absorption materials with wider EAB and lower RL.

Dual-band metamaterial absorber with stable absorption performance based on fractal structure

2021 ◽  
Author(s):  
Shuguang Fang ◽  
Lianwen Deng ◽  
Pin Zhang ◽  
Lei-Lei Qiu ◽  
Haipeng Xie ◽  
...  
Keyword(s):  
Fractal Structure ◽  
Low Cost ◽  
Impedance Matching ◽  
Metamaterial Absorber ◽  
Dual Band ◽  
Fractal Structures ◽  
Absorption Bands ◽  
Electromagnetic Resonance ◽  
Absorption Performance ◽  
Multi Band

Abstract In this paper, two kinds of dual-band metamaterial absorbers (MMAs) with stable absorption performance based on fractal structures are proposed. As the key feature, with the increase in fractal order, the fractal MMAs can reduce the weight while keeping the absorption performance. The multi-band absorption property is analyzed by multiple L-C resonances generated by the fractal structure. By virtue of good impedance matching characteristics and the synergy of the circuit and electromagnetic resonance, effective and stable microwave absorption is readily achieved. Finally, two prototypes are fabricated for demonstration, and the measurement result is consistent well with the simulation one. As expected, the proposed fractal MMAs have the advantage of low-cost, light-weight, and dual-effective absorption bands, and have great potential in the application of multi-band radar stealth.

scholarly journals Facile Preparation, Characterization, and Highly Effective Microwave Absorption Performance of CNTs/Fe3O4/PANI Nanocomposites

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Deqing Zhang ◽  
Xiuying Yang ◽  
Junye Cheng ◽  
Mingming Lu ◽  
Bin Zhao ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
In Situ Polymerization ◽  
Weight Ratio ◽  
Peak Frequency ◽  
Aniline Monomer ◽  
Transmission Electron ◽  
Absorption Performance ◽  
Additional Process ◽  
5 Ghz

A facile method has been developed to synthesize light-weight CNTs/Fe3O4/PANI nanocomposites. The formation route was proposed as the coprecipitation of Fe2+and Fe3+and an additional process of in situ polymerization of aniline monomer. The structure and morphology of CNTs/Fe3O4/PANI were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy. The TEM investigation shows that the CNTs/Fe3O4/PANI nanocomposites exhibit less intertwined structure and that many more Fe3O4particles are attached homogeneously on the surface of CNTs, indicating that PANI can indeed help CNTs to disperse in isolated form. The wave-absorbing properties were investigated in a frequency of 2–18 GHz. The results show that the CNTs/Fe3O4/PANI nanocomposites exhibit a super absorbing behavior and possess a maximum reflection loss of −48 dB at 12.9 GHz, and the bandwidth below −20 dB is more than 5 GHz. More importantly, the absorption peak frequency ranges of the CNTs/Fe3O4/PANI composites can be tuned easily by changing the wax weight ratio and thickness of CNTs/Fe3O4/PANI paraffin wax matrix.

scholarly journals Microwave induced in-situ formation of SiC nanowires on SiCNO ceramic aerogels with excellent electromagnetic wave absorption performance

2021 ◽  
Author(s):  
Keke Yuan ◽  
Daoyang Han ◽  
Junfang Liang ◽  
Wanyu Zhao ◽  
Mingliang Li ◽  
...  
Keyword(s):  
Phase Composition ◽  
High Speed ◽  
Impedance Matching ◽  
Interfacial Polarization ◽  
Microwave Treatment ◽  
Treatment Temperature ◽  
Effective Bandwidth ◽  
Composite Aerogels ◽  
Environmental Robustness

AbstractElectromagnetic absorption (EMA) materials with light weight and harsh environmental robustness are highly desired and crucially important in the stealth of high-speed vehicles. However, meeting these two requirements is always a great challenge, which excluded the most attractive lightweight candidates, such as carbon-based materials. In this study, SiCnw-reinforced SiCNO (SiCnw/SiCNO) composite aerogels were fabricated through the in-situ growth of SiCnw in polymer-derived SiCNO ceramic aerogels by using catalyst-assisted microwave heating at ultra-low temperature and in short time. The phase composition, microstructure, and EMA property of the SiCnw/SiCNO composite aerogels were systematically investigated. The results indicated that the morphology and phase composition of SiCnw/SiCNO composite aerogels can be regulated easily by varying the microwave treatment temperature. The composite aerogels show excellent EMA property with minimum reflection loss of −23.9 [email protected] GHz, −26.5 [email protected] GHz, and −20.4 [email protected] GHz and the corresponding effective bandwidth of 5.2 GHz, 3.2 GHz, and 4.8 GHz at 2.0 mm thickness for microwave treatment at 600 °C, 800 °C, and 1000 °C, respectively, which is much better than that of SiCN ceramic aerogels. The superior EMA performance is mainly attributed to the improved impedance matching, multi-reflection, multi-interfacial polarization, and micro current caused by migration of hopping electrons.

scholarly journals High-efficiency and ultra-thin electromagnetic wave absorption xAl2O3-(1-x)Sr0.85Gd0.15TiO3 ceramics in X-band

2020 ◽  
Author(s):  
Hui Xie ◽  
Chaoqun Yang ◽  
Yingying Zhou ◽  
Zhaowen Ren ◽  
Ping Liu
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
High Efficiency ◽  
Impedance Matching ◽  
Frequency Dispersion ◽  
Interfacial Polarization ◽  
Peak Frequency ◽  
Microwave Absorbing Materials ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Abstract xAl2O3-(1-x)Sr0.85Gd0.15TiO3(x=0.2, 0.3, 0.4, 0.5) ceramics were fabricated by hot-press sintering. Their morphology, phase composition, conductivity, dielectric properties as well as microwave absorption performance were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), multifunction digital four-probe meter and vector network analysis, respectively. The microwave absorption of as-prepared xAl2O3-(1-x)Sr0.85Gd0.15TiO3 ceramics demonstrates excellent microwave absorbability. It is unexpectedly found that with a thickness of only 0.346 mm, xAl2O3-(1-x)Sr0.85Gd0.15TiO3 (x=0.2) ceramic exhibits an absorption bandwidth of 3.7 GHz (8.7-12.4 GHz), being consequential to reflection loss less than -10 dB (over 90% of microwave absorption). It is as well discovered that the minimum reflection loss and absorption peak frequency of xAl2O3-(1-x)Sr0.85Gd0.15TiO3 (x=0.3) with a thickness of 0.436 mm were -45.43 dB and 11.3 GHz, respectively. The prominent microwave absorption performance of the ceramic with such a thin thickness can be attributed to strong interfacial polarization, dielectric frequency dispersion, and good electromagnetic impedance matching. It indicates that the xAl2O3-(1-x)Sr0.85Gd0.15TiO3 ceramics with appropriate Al2O3 mass fraction and thickness showing good potential for effective microwave absorbing materials.

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