The synergistic effects of carbon coating and micropore structure on the microwave absorption properties of Co/CoO nanoparticles

2016 ◽  
Vol 18 (44) ◽  
pp. 30507-30514 ◽  
Author(s):  
Xiubo Xie ◽  
Yu Pang ◽  
Hiroaki Kikuchi ◽  
Tong Liu
Keyword(s):  
Microwave Absorption ◽  
Vapor Deposition ◽  
Carbon Coating ◽  
Synergistic Effects ◽  
Impedance Matching ◽  
Chemical Vapor ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Micropore Structure ◽  
Coo Nanoparticles

Microporous Co/CoO/C nanoparticles prepared by combining chemical dealloying and chemical vapor deposition methods exhibited high microwave absorption properties due to the synergistic effects of the carbon coating and the micropore structure on the impedance matching of the absorber.

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.

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.

A Comparable Study on the Microwave Absorption Properties of Al/Fe/Co Doped OMC/Paraffin Wax Composites

NANO ◽  
2016 ◽  
Vol 11 (02) ◽  
pp. 1650014 ◽  
Author(s):  
Yanyan Ren ◽  
Hongfeng Li ◽  
Guanglei Wu ◽  
Le Yang ◽  
Chenhui Zheng ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Impedance Matching ◽  
Paraffin Wax ◽  
Frequency Range ◽  
Great Role ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Broadband Absorption ◽  
Ordered Mesoporous ◽  
Co Doped

Al/Fe/Co doped ordered mesoporous carbon (OMC) composites have been synthesized by a facile method, and the influence of dopant on the electromagnetic (EM) and microwave absorption properties was investigated in the frequency range of 2–18[Formula: see text]GHz. Compared with Fe/Co–OMC composites, the Al–OMC nanocomposite played a great role in adjusting values and frequency dependence of complex permittivity, which gives rise to significant improved microwave absorption and reduced thickness of the corresponding paraffin wax composites. Reflection loss (RL) values less than [Formula: see text]5[Formula: see text]dB and [Formula: see text]10[Formula: see text]dB were obtained in the frequency range of 9.2–18[Formula: see text]GHz and 10.7–14.7[Formula: see text]GHz with a single thickness of 2.00[Formula: see text]mm, respectively. Such enhanced EM wave absorption property of the Al–OMC/paraffin wax composite was ascribed to its superior impedance matching characteristic. Thin thickness, broadband absorption microwave absorbers with Al doped OMC nanocomposites were obtained.

Fabrication of Flaky Magnetic Composite Particles

2012 ◽  
Vol 490-495 ◽  
pp. 2628-2631
Author(s):  
Wen Qiang Zhang
Keyword(s):  
Vapor Deposition ◽  
Broad Band ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Complex Permeability ◽  
Composite Particles ◽  
Magnetic Composite ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties

Diatomite coated with ɑ-Fe films were obtained by Chemical Vapor Deposition process. The resultant Fe-coated flaky diatomite particles had low densities. The results show that Fe coated diatomite flakes can be achieved, and that the coating consisted of ɑ-Fe nano-crystallite. The complex permeability and permittivity of the composites were measured in the frequency range of 1–18 GHz. The microwave absorption properties of these flaky particles are discussed. The results indicate that the flaky particles have potential to be used as a lightweight broad band microwave absorber.

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.

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