scholarly journals The Preparation of FeCo/ZnO Composites and Enhancement of Microwave Absorbing Property by Two-Step Method

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3259
Author(s):  
Ka Gao ◽  
Junliang Zhao ◽  
Zhongyi Bai ◽  
Wenzheng Song ◽  
Rui Zhang
Keyword(s):  
Single Phase ◽  
Effective Bandwidth ◽  
Frequency Range ◽  
Step Method ◽  
Absorption Properties ◽  
Composite Surface ◽  
Microwave Absorbing Properties ◽  
Microwave Absorbing Property ◽  
Microwave Absorbing ◽  
Absorbing Property

In this paper, the flower-like FeCo/ZnO composites were successfully firstly prepared by a two-step method, and their microstructures and microwave absorbing properties were characterized. The results show that with an increase of temperature, the content of ZnO loaded on a FeCo/ZnO composite surface was increased. The optimal reflection loss (RL) value can be reached around −53.81 dB at 9.8 GHz, which is obviously superior to results of previous studies and reports, and its effective bandwidth (RL < −10 dB) is 3.8 GHz in the frequency range of 8.7–11.8 GHz with a matching thickness of 1.9 mm. We considered that a large number of lamellar and rod-like ZnO loaded on nano-FeCo single-phase solid solution by two-step method can significantly improve the electromagnetic wave absorption properties.

Effect of Structure Modification on the Microwave Absorbing Performance of Carbon Foams

2011 ◽  
Vol 197-198 ◽  
pp. 536-539 ◽  
Author(s):  
Zhi Gang Fang ◽  
Yu Xin Gao ◽  
Chun Fang
Keyword(s):  
Electric Conductivity ◽  
Carbon Foam ◽  
Structure Design ◽  
Structure Modification ◽  
Replication Process ◽  
Microwave Absorbing Properties ◽  
Carbon Foams ◽  
Microwave Absorbing Property ◽  
Microwave Absorbing ◽  
Absorbing Property

Carbon foams were prepared by a polymer sponge replication process and their microwave absorbing properties were investigated. The electric conductivity of carbon foam has a direct effect on its microwave absorbing property, as the carbon foam with a medium electric conductivity of 0.46S/m has got a relatively excellent microwave absorbing property and demonstrated a characteristic of broadband absorption. Some structure modification has been made on carbon foams to fruther imrove their microwave absorbing performance. The result shows that making slots, especially gradient slots on the surface of carbon foams can greatly improve their microwave absorbing properties, while the reflection coefficients for a three-layered carbon foam structure exceeds -10dB with the combination effect of multilayer structure design and parameters gradient variatioin in the whole frequency range of 2.6-18GHz, which is usually to be considered as the practical application standard for microwave absorbing materials.

Synthesis of NiO@C Composites with Microwave Absorption Property

2011 ◽  
Vol 311-313 ◽  
pp. 76-79
Author(s):  
Yuan Guang Zhang ◽  
Ying Guo Zhao ◽  
Qi Zhi Yao
Keyword(s):  
Frequency Range ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Peg 400 ◽  
Microscopy Image ◽  
Microwave Absorbing Property ◽  
Microwave Absorbing ◽  
Hydrothermal Approach ◽  
Absorbing Property

Carbon-encapsulated NiO (NiO@C) sphere-like composites were synthesized at 170 °C for 12h by a one-pot hydrothermal approach. Ni(Ac)2•4H2O, sucrose, and PEG-400, were selected as a precursor materials. X-ray diffraction analysis (XRD) and scanning electron microscopy image show the products of NiO@C sphere-like composites by the present process. Microwave-absorbing measurement shows the NiO@C composites exhibit good microwave absorbing property. The reflection loss (RL) values of the products are lower than −10 dB in the frequency range of 2–18 GHz with value as low as −40 dB at 2 GHz.

Synthesis and Microwave Absorbing Properties of Ni/SiO2 Core/Shell Particles

2010 ◽  
Vol 160-162 ◽  
pp. 945-950
Author(s):  
Bo Chong Wang ◽  
Tao Wang ◽  
Liang Qiao ◽  
Fa Shen Li
Keyword(s):  
Impedance Match ◽  
Core Shell ◽  
Frequency Range ◽  
Soft Magnetic ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Microwave Absorbing Properties ◽  
Hydrolysis Method ◽  
Microwave Absorbing ◽  
Shell Particles

In this paper, we report on the microwave absorbing properties of the Ni/SiO2 core/shell soft magnetic material which was synthesized by the tetraethyl orthosilicate (TEOS) hydrolysis method. The SEM patterns were shown that the particles of Ni/SiO2 were more dispersed and homogeneous. Microwave absorbing properties were measured in the range of 0.1–18 GHz. A reflection loss (RL) exceeding −20 dB in the frequency range of 2.6–8.9 GHz was achieved for an absorber thickness of 2.0–5.6 mm, and an optimal RL of −49.5 dB was obtained at 4.4 GHz for the thickness of 3.5 mm. The good microwave absorption properties resulted from a proper impedance match as a consequence of the insulator SiO2 around Ni particles.

scholarly journals Preparation and microwave-absorbing property of BaFe12O19 nanoparticles and BaFe12O19/Fe3C/CNTs composites

RSC Advances ◽  
2015 ◽  
Vol 5 (111) ◽  
pp. 91665-91669 ◽  
Author(s):  
Liangjun Yin ◽  
Tong Chen ◽  
Shiyu Liu ◽  
Yuqi Gao ◽  
Biao Wu ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Great Improvement ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Chemical Vapor Deposition Process ◽  
Microwave Absorbing Properties ◽  
Microwave Absorbing Property ◽  
Microwave Absorbing ◽  
Absorbing Property

A novel kind of BaFe12O19/Fe3C/CNTs composite was developed by the acetylene chemical vapor deposition process. The composites perform great improvement in the microwave absorbing properties compared with pure BaFe12O19 ferrite in 2–18 GHz range.

scholarly journals Structural, Magnetic, and X-Band Microwave Absorbing Properties of Ni-Ferrites Prepared Using Oxidized Mill Scales

2021 ◽  
Vol 21 (1) ◽  
pp. 27
Author(s):  
Ardita Septiani ◽  
Novrita Idayanti ◽  
Tony Kristiantoro ◽  
Dedi Mada ◽  
Nadya Larasati Kartika ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Raw Materials ◽  
Energy Dispersive Spectrometer ◽  
Milling Process ◽  
Microwave Properties ◽  
Heating Process ◽  
Microwave Absorbing Properties ◽  
X Band ◽  
Microwave Absorbing

This study aims to evaluate the structural, magnetic, and microwave absorbing properties at the X-band region of oxidized mill scales as by-product derived from a steel making process by means of a facile solid-state reaction. The oxidized mill scales were heated at 600 °C for 4 h followed by mixing with NiO. A calcination process took place at 900 °C and sintering process were conducted at 1260 °C with a milling process conducted in between the heating process. X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS) were employed to evaluate the structural properties of the Ni-ferrites samples. Remacomp measurement were conducted to evaluate the magnetic properties and vector network analyzer (VNA) to measure its microwave properties. A single phase of NiFe2O4 was confirmed by XRD data. The site occupancies derived from the Rietveld refinement shows that the Ni:Fe:O ratio deviates from the 1:2:4 ratio as that suggests vacancies formed in the Ni2+ and Fe3+ that lowers the unit cell density to 5.08 g/cm3 that further confirmed by EDS measurement. The coercivity of 11 kOe is also higher than the bulk NiFe2O4¬ prepared by the chemical grade raw materials. The reflection data of the microwave properties at X-band of 8-12 GHz do not shows significant absorptions. This study suggests that the selected preparation method yields a single phase, however with the significant crystallographic defects and has less ‘soft’ magnetic properties compared to NiFe2O4 prepared using chemical grade by previous study.

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 Enhanced low-frequency microwave absorbing property of SCFs@TiO2 composite

2018 ◽  
Vol 333 ◽  
pp. 153-159 ◽  
Author(s):  
Hongjing Wu ◽  
Shaohua Qu ◽  
Kejun Lin ◽  
Yuchang Qing ◽  
Liuding Wang ◽  
...  
Keyword(s):  
Low Frequency ◽  
Microwave Absorbing Property ◽  
Microwave Absorbing ◽  
Absorbing Property
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