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.

A facile low temperature method for the synthesis of CoFe2O4 nanoparticles possessing excellent microwave absorption properties

RSC Advances ◽  
2015 ◽  
Vol 5 (63) ◽  
pp. 51130-51134 ◽  
Author(s):  
D. Moitra ◽  
S. Hazra ◽  
B. K. Ghosh ◽  
R. K. Jani ◽  
M. K. Patra ◽  
...  
Keyword(s):  
Low Temperature ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Precipitation Method ◽  
Cofe2o4 Nanoparticles ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Temperature Method ◽  
Co Precipitation ◽  
Minimum Reflection Loss

CoFe2O4 nanoparticles, synthesized via a co-precipitation method at 120 °C, exhibited excellent microwave absorption properties, with minimum reflection loss of −55 dB (∼99.99%) at 9.25 GHz.

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.

Prepared and Microwave-Absorption Properties of BN Coated Ni Nanocapsules

2010 ◽  
Vol 663-665 ◽  
pp. 1252-1255 ◽  
Author(s):  
Gui Mei Shi ◽  
Shu Lian ◽  
Ge Song ◽  
Jin Bing Zhang
Keyword(s):  
Reflection Loss ◽  
Electromagnetic Properties ◽  
Mechanochemical Reaction ◽  
Network Analyzer ◽  
Absorber Thickness ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
X Ray ◽  
Transmission Electron

BN coated Ni nanocapsules were prepared by arc evaporating Ni-B amorphous alloy powders synthesized by a mechanochemical reaction, and their microstructure, surface component as well as electromagnetic properties (2-18 GHz) were investigated by means of high-resolution transmission electron microscopy, X-ray diffraction , photoluminescence spectra (PL) and a network analyzer, respectively. The reflection loss R (dB) of the nanocapsules less than -20 dB was obtained in the frequency range of 4.3-18 GHz for an absorber thickness of 1.4-6 mm. An optimal reflection loss of -32.0 dB was reached at 13 GHz with an absorber thickness of 2 mm. The microwave absorptive mechanisms of BN-coated Ni nanocapsule absorbent were discussed.

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.

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.

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