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.

Bimetallic MOF-derived porous CoNi/C nanocomposites with ultra-wide band microwave absorption properties

2019 ◽  
Vol 43 (42) ◽  
pp. 16546-16554 ◽  
Author(s):  
Chang Liu ◽  
Jing Qiao ◽  
Xue Zhang ◽  
Dongmei Xu ◽  
Nannan Wu ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Fine Particles ◽  
Wide Band ◽  
Ultra Wide Band ◽  
Target Product ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Microwave Absorbing Properties ◽  
Microwave Absorbing ◽  
Distributed Elements

The CoNi bimetallic MOF-derived composites were synthesized in this work. The target product is composed of fine particles with uniformly distributed elements of Ni, Co, C. The CoNi/C-650 sample displays good microwave absorbing properties.

scholarly journals Controlling the electric permittivity of honeycomb-like core–shell Ni/CuSiO3 composite nanospheres to enhance microwave absorption properties

RSC Advances ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 1172-1180 ◽  
Author(s):  
Rambabu Kuchi ◽  
Taha Latif ◽  
Sung Woo Lee ◽  
Viet Dongquoc ◽  
Phuoc Cao Van ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Impedance Matching ◽  
Core Shell ◽  
Electric Permittivity ◽  
Next Generation ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Microwave Absorbing Materials ◽  
Absorbing Materials ◽  
Microwave Absorbing

Controlling impedance matching and enhancing absorption properties are crucial for developing next-generation microwave absorbing materials.

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.

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.

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

Microwave Absorbing Properties of Polymer Composites Containing High-Permeability Magnetic Flake Particles in Quasi-Microwave Frequency Band

2013 ◽  
Vol 646 ◽  
pp. 14-17 ◽  
Author(s):  
Sung Soo Kim
Keyword(s):  
Frequency Band ◽  
Magnetic Permeability ◽  
Magnetic Particles ◽  
Impedance Matching ◽  
Microwave Frequency ◽  
Rubber Matrix ◽  
Al Alloy ◽  
Magnetic Composite ◽  
Microwave Absorbing Properties ◽  
Microwave Absorbing

This study investigates high-frequency magnetic, dielectric, and microwave absorbing properties of Sendust (Fe-Si-Al alloy) flake particles dispersed in rubber matrix for the design of thin microwave absorbers in quasi-microwave frequency band. At high particle loading (92% in weight) in the magnetic composite, reflection loss of -9 dB was obtained at 2 GHz with a small thickness of 1 mm. The result is attributed to the high values of magnetic permeability and dielectric constant of the composites resulting from a low eddy current loss (increase of permeability) of the flake particles and enhancement of space charge polarization (increase of permittivity) between the metallic particles. However, the investigation of impedance matching reveals that the magnetic permeability is still small to satisfy the zero-reflected condition at the quasi-microwave frequency band of 1-2 GHz with a composite thickness smaller than 1 mm. It is suggested that greater magnetic permeability (by control of composition and shape of magnetic particles) is required for more improved microwave absorbance at a quasi-microwave frequency.

Interfacial polarizations induced by incorporating traditional perovskites into reduced graphene oxide (RGO) for strong microwave response

2019 ◽  
Vol 48 (7) ◽  
pp. 2359-2366 ◽  
Author(s):  
Sisi Dai ◽  
Bin Quan ◽  
Baoshan Zhang ◽  
Xiaohui Liang ◽  
Guangbin Ji
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Hydrothermal Method ◽  
Reduced Graphene Oxide ◽  
Impedance Matching ◽  
Microwave Response ◽  
Simple Hydrothermal Method ◽  
High Impedance ◽  
Reduced Graphene ◽  
Microwave Absorbing

The as-prepared La0.7Sr0.3MnO3/RGO nanocomposites were synthesized via a simple hydrothermal method to provide excellent microwave absorbing performance resulting from good electrical conductivity and high impedance matching.

Improved dielectric properties and microwave absorbing properties of SiC Nanorods/Ni core-shell structure

2017 ◽  
Vol 10 (06) ◽  
pp. 1750069 ◽  
Author(s):  
Huijing Yang ◽  
Qinglu Wang ◽  
Li Wang ◽  
Zelin Zhang ◽  
Yuanlin Li ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Microwave Absorption ◽  
Shell Structure ◽  
Solution Method ◽  
Core Shell ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Microwave Absorbing Properties ◽  
Core Shell Structure ◽  
Microwave Absorbing

We synthesized SiC nanorods/Ni core-shell structure (SiCR-Ni) by a facile solution method and researched their dielectric and microwave absorption properties. The dielectric and microwave absorbing properties of SiCR-Ni are superior to SiC nanorods (SiC[Formula: see text]. The maximum absorption peak of SiCR-Ni is almost three times that of SiCR. The bandwidth of effective absorption of SiCR-Ni covers 64% of [Formula: see text]-band. The improved properties of SiCR-Ni originate from multi-polarization in the special core-shell structure of SiCR-Ni.

Air@rGO€Fe3O4 microspheres with spongy shells: self-assembly and microwave absorption performance

2016 ◽  
Vol 4 (44) ◽  
pp. 10518-10528 ◽  
Author(s):  
Qiang Zeng ◽  
Xu-hai Xiong ◽  
Ping Chen ◽  
Qi Yu ◽  
Qi Wang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Microwave Absorption ◽  
Self Assembly ◽  
Calcination Process ◽  
Emulsion Technique ◽  
Microwave Absorbing Properties ◽  
Absorption Performance ◽  
Microwave Absorbing ◽  
Fe3o4 Microspheres ◽  
Microwave Absorption Performance

Novel Air@rGO€Fe3O4 microspheres with excellent microwave absorbing properties and corrosion resistance were synthesized by a W/O emulsion technique followed by a calcination process.

scholarly journals Investigation of the Microwave Absorption of Asphalt Mixtures Containing Magnetite Powder

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 813 ◽  
Author(s):  
Bowen Guan ◽  
Jianan Liu ◽  
Hua Zhao ◽  
Jiayu Wu ◽  
Jingyi Liu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Heating Rate ◽  
Microwave Heating ◽  
Microwave Absorption ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Water Stability ◽  
Microwave Absorbing Properties ◽  
Microwave Absorbing

This article is intended to investigate the microwave heating performance of asphalt mixtures containing magnetite powders (MPAM). For this purpose, the surface temperatures of asphalt mixtures containing different dosages of magnetite powders were measured during microwave heating. The low-temperature bending test and water sensitivity test were also conducted to evaluate the performance of MPAM. Heating rate and reflection loss of different thicknesses of MPAM were determined using a microwave heating test and arch reflectivity test, respectively. The results showed that because its main components are triiron tetroxide and iron oxide, which have excellent microwave-absorbing properties, magnetite powders can be used as microwave absorbers to improve the ability of microwave absorption and increase the heating rate of asphalt mixtures. The heating rate of the asphalt mixtures increased with the increase of the amount of magnetite powder. The addition of magnetite powder improved the low-temperature properties of the asphalt mixture, but it reduced the water stability of the asphalt mixture. Considering that the microwave-absorbing asphalt mixture used for melting snow and ice should have good water stability, the recommended dosage of magnetite powders was 60%. The microwave-absorbing properties of MPAM were related to its thickness in the pavement structure and frequency of microwaves. In order to greatly enhance the absorbing efficiency, future work should be focused on matching thickness and matching frequency.

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