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 ◽  
...  

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.

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Hongyan Xu ◽  
Zhenyin Hai ◽  
Jiangtao Diwu ◽  
Qiang Zhang ◽  
Libo Gao ◽  
...  

The core-shell structured Co3O4-PANI nanocomposites have been successfully prepared using an in situ polymerization method, while the core Co3O4 nanoparticles were synthesized by carbon-assisted method using degreasing cotton as a template. The obtained samples were characterized by XRD, TEM, FTIR, and XPS. The results indicated that the amorphous PANI was well covered on the surface of the spinel Co3O4 and the Co3O4-PANI with core-shell structure was formed with particle size of about 100 nm. The interfacial interaction of the core-shell nanocomposite greatly enhances the microwave absorption properties. The maximum reflection loss of Co3O4-PANI is up to −45.8 dB at 11.7 GHz with a thickness of 2.5 mm and the adsorption bandwidth with the reflection loss below −10 dB reaches 14.1 GHz ranging from 3.9 to 18 GHz when the thickness is between 2 and 5.5 mm. Therefore, the facilely synthesized and low-cost Co3O4-PANI nanocomposite with superior microwave absorption properties can be a promising nanomaterial for high efficient microwave absorption.


2011 ◽  
Vol 374-377 ◽  
pp. 1541-1544 ◽  
Author(s):  
Yu Lan Cheng ◽  
Ping Xia ◽  
Ke Xiang Wei ◽  
Quan Bai

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.


2020 ◽  
Vol 20 (3) ◽  
pp. 1756-1764 ◽  
Author(s):  
Peng Chen ◽  
Lin-Wen Jiang ◽  
Shan-Shan Yang ◽  
Hong-Bing Chen ◽  
Jun He ◽  
...  

Organic–inorganic CoFe2O4/polyaniline (CoFe2O4/PA) nanocomposites with embedded structures were synthesized by combining the sol–gel auto-combustion process and in-situ oxidative polymerization. The phases and morphologies of the prepared samples were identified. The pure CoFe2O4 samples exhibited inferior microwave-absorption properties in a frequency range of 2–18 GHz. Upon the incorporation of PA, the formed CoFe2O4/PA nanocomposites exhibited rather good absorption performances. When the sample thickness was 2.5 mm, the maximum reflection loss (RL) reached -22.3 dB, while the RL below -10 dB corresponded to the range of 11.0–17.1 GHz, which contains almost the entire Ku-band, making the structure promising for commercial and military applications. A physical model was employed to explain the effects of the embedded structure on the microwave-absorption performances. The excellent microwave-absorption performances could be attributed to the interfacial polarization and repeated reflection of the microwaves inside the CoFe2O4/PA composite.


NANO ◽  
2020 ◽  
Vol 15 (03) ◽  
pp. 2050032 ◽  
Author(s):  
Wentong Yang ◽  
Xiansen Yang ◽  
Xiang Li ◽  
Md. Zahidul Islam ◽  
Yubing Dong ◽  
...  

In this paper, we designed a core@double-shell nanostructure to enhance the electromagnetic wave absorption performance of hybrid nanospheres. Herein, the core@double-shell structured Fe3O4@polyaniline@MnO2 nanospheres were successfully prepared by a facile solvothermal process and in situ polymerization methods. The morphology, structure, magnetism and microwave absorption properties were studied. The results reveal that the FPM nanospheres exhibit extraordinary microwave absorbing performance compared to those of either Fe3O4 or Fe3O4@polyaniline nanospheres. The minimum reflection loss of the FPM nanospheres is [Formula: see text]14.7[Formula: see text]dB at 15.76[Formula: see text]GHz with the thickness of 3.5[Formula: see text]mm, and the corresponding effective absorption bandwidth can reach 4.75[Formula: see text]GHz. The perfect EMW absorption of nanospheres can be ascribed to multi-interface polarization, multiple reflections and good impedance matching originated from the core@double-shell nanostructure.


2010 ◽  
Vol 148-149 ◽  
pp. 893-896 ◽  
Author(s):  
Ze Yang Zhang ◽  
Xiang Xuan Liu ◽  
You Peng Wu

M-typical SrFe12O19 ferrites and FeNi3 nanoplatelets were successfully prepared by the sol-gel method and solution phase reduction method, respectively. The crystalline and morphology of particles were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The composite coatings with SrFe12O19 ferrites and FeNi3 nanoplatelets in polyvinylchloride matrix were prepared. The microwave absorption properties of these coatings were investigated in 2-18GHz frequency range. The results showed that the M-typical SrFe12O19 ferrites and FeNi3 nanoplatelets were obtained and they presented irregular sheet shapes. With the increase of the coating thickness, the absorbing peak value moves to the lower frequency. The absorbing peak values of the wave increase along with the increasing of the content of FeNi3 nanoplatelets filling fraction. When 40% SrFe12O19 ferrites is doped with 20% mass fraction FeNi3 nanoplatelets to prepare composite with 1.5mm thickness, the maximum reflection loss is -24.8 dB at 7.9GHz and the -10 dB bandwidth reaches 3.2GHz.


2009 ◽  
Vol 67 ◽  
pp. 59-64 ◽  
Author(s):  
Rahul Sharma ◽  
Ramesh Chandra Agarwala ◽  
Vijaya Agarwala

Nano radar absorbing material (NRAM) i.e. BaMe2Fe16O27 (Me2+=Fe2+) powder (10 nm) is coated with amorphous Ni-P nano layer (5-10 nm) by using electroless (EL) technology to develop EL Ni-P/NRAM nanocomposite powder. The experimental processes parameters and EL Ni-P bath composition were optimized to obtain the deposition. As-deposited nanocomposite powder was microwave annealed (MWA) with increasing radiation power from 160 to 760 watts for 5 minutes. The surface morphology, elemental contents, phase transformation and magnetic properties of NRAM powders were examined under field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) respectively. Maximum reflection loss (RL) 33.75 dB at 15.80 GHz for nanocomposite powder MWA at 760 watt was obtained the absorption range under −15 dB is from 13.76 to 16.77 GHz with 2 mm thickness layer in Ku Band. Excellent microwave absorption properties due to accurate electromagnetic (EM) match in the nanocomposite microstructure, a strong natural resonance and multipolarization. Such (Ni+ Ni3P)/NRAM nanocomposite powders may be attractive candidates for EM absorption.


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