Pyrolysis-controlled FeCoNi@hard carbon composites with facilitated impedance matching for strong electromagnetic wave response

2021 ◽  
Vol 9 (38) ◽  
pp. 13447-13459
Author(s):  
Junyao Shen ◽  
Danfeng Zhang ◽  
Qibai Wu ◽  
Yan Wang ◽  
Heng Gao ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Microwave Absorption ◽  
Impedance Matching ◽  
Carbon Composites ◽  
Hard Carbon ◽  
Microwave Absorbers ◽  
Strong Electromagnetic Wave ◽  
Wave Response

FeCoNi@hard carbon (HC) microwave absorbers were prepared from FeCoNi nanosheets@polyimide (PI) using suitable pyrolysis temperatures and showed excellent microwave absorption performances with enhanced impedance matching.

scholarly journals Solvent-Free Synthesis of Ultrafine Tungsten Carbide Nanoparticles-Decorated Carbon Nanosheets for Microwave Absorption

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Yunlong Lian ◽  
Binhua Han ◽  
Dawei Liu ◽  
Yahui Wang ◽  
Honghong Zhao ◽  
...  
Keyword(s):  
Tungsten Carbide ◽  
Microwave Absorption ◽  
Impedance Matching ◽  
Weight Ratio ◽  
Solvent Free ◽  
Carbon Composites ◽  
Carbon Nanosheets ◽  
Solid Mixture ◽  
Absorption Performance ◽  
Microwave Absorption Performance

AbstractCarbides/carbon composites are emerging as a new kind of binary dielectric systems with good microwave absorption performance. Herein, we obtain a series of tungsten carbide/carbon composites through a simple solvent-free strategy, where the solid mixture of dicyandiamide (DCA) and ammonium metatungstate (AM) is employed as the precursor. Ultrafine cubic WC1−x nanoparticles (3–4 nm) are in situ generated and uniformly dispersed on carbon nanosheets. This configuration overcomes some disadvantages of conventional carbides/carbon composites and is greatly helpful for electromagnetic dissipation. It is found that the weight ratio of DCA to AM can regulate chemical composition of these composites, while less impact on the average size of WC1−x nanoparticles. With the increase in carbon nanosheets, the relative complex permittivity and dielectric loss ability are constantly enhanced through conductive loss and polarization relaxation. The different dielectric properties endow these composites with distinguishable attenuation ability and impedance matching. When DCA/AM weight ratio is 6.0, the optimized composite can produce good microwave absorption performance, whose strongest reflection loss intensity reaches up to − 55.6 dB at 17.5 GHz and qualified absorption bandwidth covers 3.6–18.0 GHz by manipulating the thickness from 1.0 to 5.0 mm. Such a performance is superior to many conventional carbides/carbon composites.

Magnetic hollow mesoporous carbon composites with impedance matching for highly effective microwave absorption

2018 ◽  
Vol 54 (5) ◽  
pp. 4024-4037 ◽  
Author(s):  
Guozhu Shen ◽  
Junzhao Ren ◽  
Bin Zhao ◽  
Buqing Mei ◽  
Hongyan Wu ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Mesoporous Carbon ◽  
Impedance Matching ◽  
Carbon Composites ◽  
Highly Effective

Direct synthesis of MOF-derived nanoporous CuO/carbon composites for high impedance matching and advanced microwave absorption

2016 ◽  
Vol 4 (48) ◽  
pp. 11419-11426 ◽  
Author(s):  
Jianna Ma ◽  
Xingmiao Zhang ◽  
Wei Liu ◽  
Guangbin Ji
Keyword(s):  
Microwave Absorption ◽  
Direct Synthesis ◽  
Impedance Matching ◽  
Carbon Composites ◽  
Microwave Absorbing Properties ◽  
Simple Strategy ◽  
High Impedance ◽  
Microwave Absorbing

A simple strategy to fabricate porous CuO/carbon composites by nitrate impregnation into a MOF template is reported in this study. The obtained CuO/carbon samples show improved impedance matching and excellent microwave absorbing properties.

Facile synthesis of 3D Ni@C nanocomposites derived from two kinds of petal-like Ni-based MOFs towards lightweight and efficient microwave absorbers

Nanoscale ◽  
2021 ◽  
Author(s):  
Pengshu Yi ◽  
Zhengjun Yao ◽  
Jintang Zhou ◽  
Bo Wei ◽  
Ruiyang Tan ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Microwave Absorption ◽  
High Efficiency ◽  
Facile Synthesis ◽  
Microwave Absorbers ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption

The development of lightweight and high-efficiency microwave absorption materials has attracted wide attention in the field of electromagnetic wave absorption. Herein, two kinds of petal-like Ni-based MOFs were grown on...

scholarly journals Facile synthesis of highly conductive MoS2/graphene nanohybrids with hetero-structures as excellent microwave absorbers

RSC Advances ◽  
2018 ◽  
Vol 8 (64) ◽  
pp. 36616-36624 ◽  
Author(s):  
Jixing Chai ◽  
Deqing Zhang ◽  
Junye Cheng ◽  
Yixuan Jia ◽  
Xuewei Ba ◽  
...  
Keyword(s):  
Physical Properties ◽  
Microwave Absorption ◽  
Impedance Matching ◽  
Two Dimensional ◽  
Facile Synthesis ◽  
Graphene Nanosheet ◽  
Microwave Absorbers ◽  
Unique Chemical

Two-dimensional (2D) MoS2/graphene nanosheet (MoS2/GN) hybrids have been demonstrated to be promising microwave absorption (MA) materials due to their unique chemical and physical properties as well as rich impedance matching.

Core–Shell Structural Barium Ferrite/Polypyrrole Nanocomposites with Enhanced Microwave Absorption Properties

2020 ◽  
Vol 15 (11) ◽  
pp. 1312-1320
Author(s):  
Kai Sun ◽  
Gang Li ◽  
Yan-Hua Lei ◽  
Xin-Feng Wu ◽  
Wei-Guo Zhang ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Microwave Absorption ◽  
Barium Ferrite ◽  
Wave Attenuation ◽  
Magnetic Loss ◽  
Impedance Matching ◽  
Oxidative Polymerization ◽  
Electromagnetic Properties ◽  
Core Shell ◽  
Absorption Performance

In this paper, core–shell structural barium ferrite/polypyrrole (BF/PPy) nanocomposites were prepared by a facile in-situ chemical oxidative polymerization method, and their electromagnetic properties were systematically studied. It was demonstrated that the nanocomposites with 15 mol% BF possessed the best electromagnetic wave absorption performance, and a reflection loss of -57.13 dB was achieved at 3.98 mm. Further study revealed that the optimized impedance matching and large attenuation constant were conducive to a good absorption performance. Meanwhile, the combined action of dielectric loss and magnetic loss was responsible for the electromagnetic wave attenuation. This study provides a supplementary approach to microwave absorption materials with a desirable absorption performance.

scholarly journals Effect of Reaction Time on Microwave Absorption Properties of Fe3O4 Hollow Spheres Synthesized via Ostwald Ripening

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2921 ◽  
Author(s):  
Wei Huang ◽  
Yujiang Wang ◽  
Shicheng Wei ◽  
Bo Wang ◽  
Yi Liang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Microwave Absorption ◽  
Ostwald Ripening ◽  
Impedance Matching ◽  
Hollow Spheres ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Magnetic Structures ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Hollow magnetic structures have great potential to be used in the microwave absorbing field. Herein, Fe3O4 hollow spheres with different levels of hollowness were synthesized by the hydrothermal method under Ostwald ripening effect. In addition to their microstructures, the microwave absorption properties of such spheres were investigated. The results show that the grain size and hollowness of Fe3O4 hollow spheres both increase as the reaction time increases. With increasing hollowness, the attenuation ability of electromagnetic wave of Fe3O4 spheres increases first and then decreases, finally increases sharply after the spheres break down. Samples with strong attenuation ability can achieve good impedance matching, which it does preferentially as the absorber thickness increases. Fe3O4 hollow spheres show the best microwave absorption performance when the reaction time is 24 h. The minimum reflection loss (RL (min)) can reach −40 dB, while the thickness is only 3.2 mm.

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