Large-Scale Synthesis and Microwave Absorption Properties of CoFe2O4/ Co0.4Zn0.6Fe2O4 Hollow Nanospheres

2015 ◽  
Vol 645-646 ◽  
pp. 126-131
Author(s):  
Qing Guo Ren ◽  
Xiao Jing Qiao ◽  
Yan Li ◽  
Zhi Gang Sun ◽  
Xiao Dang Guo ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Large Scale ◽  
Average Diameter ◽  
Hollow Nanospheres ◽  
Magnetic Studies ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Line Theory ◽  
Glycol Solution

Monodisperse CoFe2O4and Co0.4Zn0.6Fe2O4hollow nanospheres were synthesized in large scale by solvothermal method in ethylene glycol solution. The structure, shape and size of the samples were investigated by Fourier Transform infrared, X-ray powder diffraction and scanning electron microscopy. The results indicate that the products are spherical with an average diameter less than 200 nm. Magnetic studies revealed that the saturation magnetization of Co0.4Zn0.6Fe2O4is 78.6 emu/g, higher than the CoFe2O4, which is 69 emu/g, while the coercivity of the Co0.4Zn0.6Fe2O4is 184 Oe , obviously lower than that of CoFe2O4which is 832 Oe. The electromagnetic parameters were measured at 2-18 GHz using HP8722ES vector network analyzer and then the microwave absorption properties were calculated through the transmission line theory. As to the Co0.4Zn0.6Fe2O4, the absorption bandwidth with reflection loss below-10 dB is up to 3GHz, from 10GHz to 13GHz with a thickness of 2 mm. A maximum reflection loss-45.6 dB was found at 12.9 GHz for the CoFe2O4with a thickness of 1.8 mm. As a result, the as-prepared hollow nanospheres show good prospects of being applied in EM wave absorption materials.

scholarly journals Influence of External Magnetic Field on the Microwave Absorption Properties of Carbonyl Iron and Polychloroprene Composites Film

2016 ◽  
Author(s):  
Haiyan Wang ◽  
Xueai Li
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Carbonyl Iron ◽  
Magnetic Particles ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Line Theory ◽  
Composites Film

The carbonyl iron particles were dispersed in a polychloroprene rubber (CR) matrix under an external magnetic field for practical application as microwave absorption composites film. The film prepared under external magnetic field with a thickness of only 0.54 mm showed least reflection loss of -15.98 dB and the reflection loss value less than -10.0 dB over the frequency range of 11.4~14.8 GHz. In comparison with the microwave absorption properties of calculation by transmission line theory based on the tested relative complex permittivity and permeability and film prepared by general route without external magnetic field, the film made with external magnetic field exhibited more excellent microwave absorption properties, strongly depending on the increment of anisotropy and rearrangement of magnetic particles. The results indicated the composite film made under external magnetic field have excellent microwave absorption properties, which suggest that the composites thin film could be used as a thinner and lighter microwave absorber.

Magnetization and Microwave Absorption Properties of La0.67 Sr0.33 MnO3 with Different Particle Size

2011 ◽  
Vol 374-377 ◽  
pp. 1541-1544 ◽  
Author(s):  
Yu Lan Cheng ◽  
Ping Xia ◽  
Ke Xiang Wei ◽  
Quan Bai
Keyword(s):  
Particle Size ◽  
Sinter Temperature ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Sol Gel ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Measured Frequency Range ◽  
Maximum Reflection Loss

La 0.67 Sr 0.33 MnO 3 particles with different particle size have been prepared by sol-gel method. The structure, magnetization and microwave absorption properties have been investigated. The results show that the particle size can be controlled by sinter temperature. The peaks of the maximum reflection loss (RL) move to higher frequency regions with increasing particle size. The value of the maximum RL is -32 dB at 10.2GHz with a particle size of 58.5nm. The bandwidth with a RL exceeding -8dB reached 1.6GHz in the whole measured frequency range, suggesting that La 0.67 Sr 0.33 MnO 3 particles are promising for application as a wideband and strong absorption building microwave absorber.

Temperature dependence of the electromagnetic and microwave absorption properties of polyimide/Ti3SiC2 composites in the X band

RSC Advances ◽  
2015 ◽  
Vol 5 (105) ◽  
pp. 86656-86664 ◽  
Author(s):  
Hongyu Wang ◽  
Dongmei Zhu ◽  
Wancheng Zhou ◽  
Fa Luo
Keyword(s):  
Temperature Dependence ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Absorption Bandwidth ◽  
X Band ◽  
Maximum Reflection Loss

The maximum reflection loss value of polyimide/Ti3SiC2 composites is up to −48.6 dB at 8.5 GHz with a thickness of 2.9 mm and the absorption bandwidth below −10 dB is 3.8 GHz.

Microwave Absorption Properties of BaFe12O19 Prepared in Different Temperature with Polyaniline Nanocomposites

2017 ◽  
Vol 1142 ◽  
pp. 211-215 ◽  
Author(s):  
Wang Jun Feng ◽  
Xing Zhao ◽  
Wen Qian Zheng ◽  
Jun Tao Gang ◽  
Yue Cao ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
In Situ Polymerization ◽  
Sol Gel ◽  
Ftir Spectra ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Result Show ◽  
Absorbing Material

The BaFe12O19 nanoparticles was prepared by sol-gel method in different temperature (750°C,850°Cand 950°C), and then BaFe12O19/polyaniline nanocomposites was synthesized by in situ polymerization. The XRD, FTIR spectra, SEM and vector network analyzer were used to analyze the "" chemical component, morphology and microwave absorption property of the nanocomposites. The result show that BaFe12O19 can be generated at 750°C without any impurity ,and its size increased with increase of calcination temperature.BaFe12O19 nanoparticle was coated with polyaniline partially, and we can get it have interaction with polyaniline through FTIR spectra. While the ferrite calcined at 850°C,the thickness of the absorbing material is 4.5mm,the nanocomposites have the largest reflection loss of-17.6 dB at 6 GHz,and its reflection loss values less than−10 dB in the range of 5-7.4GHz.

scholarly journals Excellent microwave absorption properties based on a composite of one dimensional Mo2C@C nanorods and a PVDF matrix

RSC Advances ◽  
2019 ◽  
Vol 9 (37) ◽  
pp. 21243-21248 ◽  
Author(s):  
Chao-Qin Li ◽  
Xun Shen ◽  
Ruo-Cheng Ding ◽  
Guang-Sheng Wang
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
One Dimensional ◽  
Absorption Performance ◽  
Pvdf Matrix ◽  
Maximum Reflection Loss

A Mo2C@C/PVDF composite with excellent absorption performance has been synthesized. The results indicate that the maximum reflection loss can reach −39.0 dB, and the absorbing bandwidth is up to 3.1 GHz at a thickness of 2.0 mm.

A novel three-dimensional Fe3SnC/C hybrid nanofiber absorber for lightweight and highly-efficient microwave absorption

2020 ◽  
Vol 22 (45) ◽  
pp. 26104-26108
Author(s):  
Guangguang Guan ◽  
Guojun Gao ◽  
Jun Xiang ◽  
Jingnan Yang ◽  
Xiaoqiang Li ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Three Dimensional ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Highly Efficient ◽  
Hybrid Nanofibers ◽  
Hybrid Nanofiber

3D Fe3SnC/C hybrid nanofibers have superior microwave absorption properties. The optimal reflection loss reaches −119.2 dB at 17.1 GHz.

scholarly journals Microwave Absorption Properties of Double-Layer RADAR Absorbing Materials Based on Doped Barium Hexaferrite/TiO2/Conducting Carbon Black

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Sukanta Das ◽  
G. C. Nayak ◽  
S. K. Sahu ◽  
P. C. Routray ◽  
A. K. Roy ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Carbon Black ◽  
Microwave Absorption ◽  
Double Layer ◽  
Reflection Loss ◽  
Barium Hexaferrite ◽  
Conducting Layer ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Absorbing Materials

In this report, we demonstrate microwave absorption properties of barium hexaferrite, doped barium hexaferrite, titanium dioxide and conducting carbon black based RADAR absorbing material for stealth application. Double-layer absorbers are prepared with a top layer consisting of 30% hexaferrite and 10% titanium dioxide while the bottom layer composed of 30% hexaferrite and 10% conducting carbon black, embedded in chloroprene matrix. The top and bottom layers are prepared as impedance matching layer and conducting layer, respectively, with a total thickness of 2 mm. Microwave absorption properties of all the composites were analyzed in X-band region. Maximum reflection loss of −32 dB at 10.64 GHz was observed for barium hexaferrite based double-layer absorber whereas for doped barium hexaferrite based absorber the reflection loss was found to be −29.56 dB at 11.7 GHz. A consistence reflection loss value (>−24 dB) was observed for doped barium hexaferrite based RADAR absorbing materials within the entire bandwidth.

Facile synthesis of porous coin-like iron and its excellent electromagnetic absorption performance

RSC Advances ◽  
2015 ◽  
Vol 5 (33) ◽  
pp. 25936-25941 ◽  
Author(s):  
Hualiang Lv ◽  
Xiaohui Liang ◽  
Yan Cheng ◽  
Guangbin Ji ◽  
Dongming Tang ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Electromagnetic Scattering ◽  
Special Structure ◽  
Facile Synthesis ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Electromagnetic Absorption ◽  
Absorption Performance

The porous coin-like iron exhibits excellent microwave absorption properties with the optimal reflection loss value of −53.2 dB at a thickness of 1.4 mm. This special structure is attributed to electromagnetic scattering behavior which is benefit for microwave absorption.

FACILE SYNTHESIS AND MICROWAVE ABSORPTION PROPERTIES OF α-MnO2 NANORODS

2012 ◽  
Vol 05 (04) ◽  
pp. 1250043 ◽  
Author(s):  
HONGTAO GUAN ◽  
GANG CHEN ◽  
JING ZHU ◽  
YUDE WANG
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Chemical Precipitation ◽  
Electromagnetic Properties ◽  
Precipitation Method ◽  
Electronic Microscopy ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
5 Ghz ◽  
Peak Value

A low-temperature water-bathing chemical precipitation method was developed to synthesize α- MnO2 nanorods. The morphological and crystalline structures were investigated by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and X-ray diffraction (XRD) spectra. The electromagnetic properties and microwave absorption properties were examined in the frequency range 2–18 GHz. The results show that the as-synthesized product is α- MnO2 nanorod with diameters of 30 nm and lengths up to 1–2 μm. The dielectric permittivity has a trend of decreasing its real and increasing its imaginary parts with the frequency. The magnetic permeability is about 1.0–1.2 and 0–0.1 for its real and imaginary parts at the whole frequency. With the increase of sample thickness, the reflection loss peak value shifts to lower frequency band. With a thickness of 3 mm, an absorption peak value of -25 dB was achieved. And its effective absorption bandwidth in which the reflection loss is lower than -10 dB is as high as 5 GHz.

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