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.

Carbon Coated Core-Shell FeSiCr/Fe3C Embedded in Carbon Nanosheets Network Nanocomposites for Improving Microwave Absorption Performance

NANO ◽  
2020 ◽  
Vol 15 (07) ◽  
pp. 2050094
Author(s):  
Houdong Xiong ◽  
Lei Wang ◽  
Sajjad Ur Rehman ◽  
Yang Chen ◽  
Qiulan Tan ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Impedance Matching ◽  
Core Shell ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Carbon Nanosheets ◽  
Practical Applications ◽  
Conduction Loss ◽  
Microwave Absorbing Materials ◽  
Carbon Coated

Development of microwave absorbing materials with tunable thickness and bandwidth is particularly important for practical applications, but its realization remains a great challenge. Here, we report carbon coated core-shell FeSiCr/Fe3C embedded in two-dimensional carbon nanosheets network (FeSiCr/Fe3C@C/C) nanocomposites fabricated by plasma arc-discharging method. FeSiCr/Fe3C@C/C has the best microwave absorption properties in which the minimum calculated reflection loss (RL) can reach [Formula: see text][Formula: see text]dB at 11.5[Formula: see text]GHz with a coating thickness of 2.4[Formula: see text]mm and the efficient absorption bandwidth (RL[Formula: see text][Formula: see text]dB) almost covers 4.5–18[Formula: see text]GHz range by adjusting the coating thicknesses from 1.3 to 5.0[Formula: see text]mm. The improved microwave absorption properties could be ascribed to the optimized impedance matching and enhanced polarization loss, conduction loss and internal reflections of the propagated microwave.

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.

Enhanced Microwave Absorption Properties of FeCo@TiO2 Core-Shell Nanoparticles

2018 ◽  
Vol 15 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Abdolrasoul Gharaati ◽  
Majid Ebrahimzadeh
Keyword(s):  
Tio2 Nanoparticles ◽  
Microwave Absorption ◽  
Core Shell ◽  
Frequency Range ◽  
Absorption Properties ◽  
Shell Nanoparticles ◽  
Microwave Absorption Properties ◽  
Band Frequency ◽  
Microwave Absorbing ◽  
Core Shell Nanoparticles

Background: Microwave absorbing nanocomposite is a kind of material that attenuates the reflection of microwave radiation in the gigahertz frequency range. These materials consist of dielectric and transition nanoparticles tend to exhibit attractive microwave absorption properties due to their high permittivity and permeability loss factors. Method: The FeCo nanoparticles were prepared from the reduction of iron and cobalt ions with hydrazine. Then, the FeCo@TiO2 core-shell nanoparticles synthesized by co-precipitation method and their microwave absorbing performance are investigated. The phase composition, morphology and coercivity properties of the nanoparticles were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The composites of FeCo@TiO2 nanoparticles with the ratio of 30 vol.% and paraffin wax (70 vol.%) in different thicknesses were prepared. The microwave absorption properties of these composites were investigated in the frequency range of 2-18 GHz using the vector network analyzer. Results: These nanocomposites exhibit the excellent microwave absorption characteristics (reflection loss<-20dB) in the bored band frequency range of 6-16 GHz with different absorber thicknesses of 1- 2.2 mm. The maximum absorption capability of -47.76 dB was obtained at the frequency of 7.92 GHz with the thickness of 1.8 mm. Based on this study, it can be argued that the FeCo@TiO2 nanoparticles can be used for the bored band and thin microwave absorbers.

Preparation and Microwave Absorption Properties of the Fe/TiO2/Al2O3 Composites

NANO ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. 1850125 ◽  
Author(s):  
Yun Li ◽  
Haifeng Cheng ◽  
Nannan Wang ◽  
Shen Zhou ◽  
Dongjin Xie ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Impedance Matching ◽  
Interfacial Polarization ◽  
Metal Nanowires ◽  
Core Shell ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Magnetic Metal ◽  
Different Diameters ◽  
Oxide Membranes

To reduce the imbalance of impedance matching between the magnetic metal nanowires and free space, Fe/TiO2 core/shell nanowire arrays with different diameters were fabricated in the templates of anodic aluminum oxide membranes by electrodeposition. The influences of the microstructure on the microwave absorption properties of the Fe/TiO2/Al2O3 composites were studied by the transmission/reflection waveguide method. It was demonstrated experimentally that both the interfacial polarization and the diameter of the Fe/TiO2 core/shell nanowires have critical effects on the microwave absorption properties. We also investigated the angle dependence of the microwave absorption properties. Due to the interfacial polarization and associated relaxation, the Fe/TiO2/Al2O3 composites exhibited optimal microwave absorption properties when microwave propagation direction was accordant with the axis of the nanowires. Finally, we managed to obtain an optimal reflection loss of below [Formula: see text]10[Formula: see text]dB (90% absorption) over 10.2–14.8[Formula: see text]GHz, with a thickness of 3.0[Formula: see text]mm and the minimum value of [Formula: see text]39.4[Formula: see text]dB at 11.7[Formula: see text]GHz.

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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