Preparation of La0.75Sr0.25Cr0.5Mn0.5O3-δ Nanometer Powders by Sol-Gel Method and Research about its Electrochemical Performance

2013 ◽  
Vol 712-715 ◽  
pp. 257-261
Author(s):  
Yin Lin Wu ◽  
Qing Hui Wang ◽  
Ling Wang ◽  
Hai Yan Zhao

The La0.75Sr0.25Cr0.5Mn0.5O3-δnanometer powders were prepared by citric acid sol-gel method.The samples were characterized by DTA, FT-IR, XRD, TEM techniques. The preparation process, morphology of synthesized powders, the best heat-treatment temperature and the electrochemical performance had been studied. The results show that the spherical nanometer powders can be obtained and the best heat-treatment temperature is 800°C. The particle size is about 30nm and Ea is 0.071 eV.

2013 ◽  
Vol 743 ◽  
pp. 179-182 ◽  
Author(s):  
Yin Lin Wu ◽  
Qing Hui Wang ◽  
Ling Wang ◽  
Hai Yan Zhao

The ZnFe2O4 nanometer powders were prepared by EDTA sol-gel method. The samples were characterized by DTA, FT-IR, XRD techniques. The preparation process, the best heat-treatment temperature and the electrochemical performance had been studied. The results show that the spherical nanometer powders can be obtained and the best heat-treatment temperature is 900°C. The particle size is about 10nm and Ea is 0.88 eV.


2014 ◽  
Vol 1078 ◽  
pp. 31-35
Author(s):  
Liang Zhao ◽  
Qun Hu Xue ◽  
Dong Hai Ding

MgO-Al2O3-ZrO2composite powders with 3 kinds of mass ratio were synthesized by sol–gel method using MgCl2·6H2O, AlCl3·6H2O and ZrOCl2·8H2O as starting materials, and NH3·H2O as a precipitant. The composite powders which match with zirconium oxide particle size and evenly distribute can are advantageous to the formation of metastable t-ZrO2and restrain the grain growth as the additive of modified sizing nozzle. Chemical composition, mineral phase, particle size distribution and micro-morphology of the composite powders were investigated by X-ray fluorescence instrument, X-ray diffractometer, laser particle size analyzer and scanning electron microscope. Research showed that under the process that the concentration of MgCl2solution 0.2 mol/L, AlCl3and ZrOCl2solution concentration 0.5 mol/L, the pH controlled between 10 ~ 11, PEG as the surfactant, drying at 70°C±5°C, heat treatment temperature at 800°C for 3h, particle size distribution of MgO-Al2O3-ZrO2composite powders were: d10= 1.28 μm, d50= 4.65μm, d90= 11.13μm (MgO 10%); d10= 1.15μm, d50= 5.80μm, d90= 15.13μm (MgO 15%);d10= 1.21μm, d50= 6.59μm, d90= 16.87μm (MgO 20%). With the rising of heat treatment temperature, the crystallization degree of composite powders increased, at 800 °C a small amount of t - ZrO2precipitated, meanwhile MgO and Al2O3are still in the amorphous phase. The MgO-A12O3-ZrO2composite powders under this condition have high reactivity and uniform distribution.


2012 ◽  
Vol 591-593 ◽  
pp. 1012-1016 ◽  
Author(s):  
Jing Ying Lu ◽  
Qing Nan Zhao ◽  
Shao Hong Hou ◽  
Yu Hong Dong

TiO2-SiO2 double-layer films are prepared on glass substrates by sol-gel method and dip dipping method. The effect of aging time, heat treatment temperature and molar content of TiO2 for the optical properties of the films have been studied on this paper. And on this basis TiO2-SiO2/SiO2 double-layer films have been prepared as well as the transmittances in the visible range of it have been studied. The results of this paper show that the transmittances of TiO2-SiO2 films in the visible range are reduced with the increasing of sol aging time, molar content of TiO2 and heat treatment temperature; The TiO2-SiO2/SiO2 double-layer films prepared on this basis have antireflective effect, and the average transmittances in the visible range of it are increased nearly 4%-5% more than glass substrate and the transmittance peak reached 100%; the surfaces of the films are smooth; in addition, the cut sides of UV of TiO2-SiO2/SiO2 double-layer films are moved to infrared with the increase of TiO2 content.


2015 ◽  
Vol 33 (4) ◽  
pp. 732-741 ◽  
Author(s):  
Anna Adamczyk

AbstractAluminosilicate materials were obtained by sol-gel method, using different Al2O3 and SiO2 precursors in order to prepare sols based on water and organic solvents. As SiO2 precursors, Aerosil 200TM and tetraethoxysilane TEOS: Si(OC2H5)4 were applied, while DisperalTM and aluminium secondary butoxide ATSB: Al(OC4H9)3 were used for Al2O3 ones. Bulk samples were obtained by heating gels at 500 °C, 850 °C and at 1150 °C in air, while thin films were synthesized on carbon, steel and alundum (representing porous ceramics) substrates by the dip coating method. Thin films were annealed in air (steel and alundum) and in argon (carbon) at different temperatures, depending on the substrate type. The samples were synthesized as gels and coatings of the composition corresponding the that of 3Al2O3·2SiO2 mullite because of the specific valuable properties of this material. The structure of the annealed bulk samples and coatings was studied by FT-IR spectroscopy and XRD method (in standard and GID configurations). Additionally, the electron microscopy (SEM) together with EDS microanalysis were applied to describe the morphology and the chemical composition of thin films. The analysis of FT-IR spectra and X-ray diffraction patterns of bulk samples revealed the presence of γ-Al2O3 and δ-Al2O3 phases, together with the small amount of SiO2 in the particulate samples. This observation was confirmed by the bands due to vibrations of Al–O bonds occurring in γ-Al2O3 and δ-Al2O3 structures, in the range of 400 to 900 cm−1. The same phases (γ-Al2O3 and δ-Al2O) were observed in the deposited coatings, but the presence of particulate ones strongly depended on the type of Al2O3 and SiO2 precursor and on the heat treatment temperature. All thin films contained considerable amounts of amorphous phase.


2008 ◽  
Vol 368-372 ◽  
pp. 800-802 ◽  
Author(s):  
Shi Ying Zhang ◽  
Fan Ping Xiao ◽  
Luo Yi Wu ◽  
Cheng Yong Li ◽  
Zhen Hua Chen

Using tetrabutyltitanate as titanium source, amorphous TiO2 powder was firstly prepared by a sol–miniemulsion–gel method. Prepared powder was refluxed in basic solution and then calcined at different temperatures to synthesize titania nanofibers. The prepared samples were characterized by XRD, TG–DSC, FT–IR and TEM. The results show that when the heat–treatment temperature increases, crystallization of the titania nanofibers occurs with two Ti–OH bonds dehydrate, meanwhile morphology of the fibers is gradually obvious and ratio of length to diameter decreases. When the temperature was raised above 550 °C, titania nanofibers were sintered.


2018 ◽  
Vol 32 (34n36) ◽  
pp. 1840069 ◽  
Author(s):  
Wei Wu ◽  
Jinshan Zhang ◽  
Pengjun Cao ◽  
Jiling Dong ◽  
Hao Ding

Sm–Co nanoparticles have promising applications in both scientific and industrial fields. In this paper, Sm–Co single-crystal nanoparticles were prepared using respective metal salts and complexing agents, such as citric acid by Pechini-type sol–gel method. The mixture solution was heated to form a highly viscous gel, and then heated at different temperatures to achieve SmCo-oxide. And then Sm–Co particles were yielded by reductive annealing of the precursors. Phase analysis, microstructural investigation and magnetic properties were performed by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Fourier transform infrared (FT-IR) and VSM. TGA trace analysis of the gel determined the heat treatment temperature. XRD results showed that SmCoO3 and Co3O4 were obtained at 800[Formula: see text]C, FT-IR spectrometry analysis also verified the results. In the calcium-thermal reduction process, Sm2O3 and Co were obtained after reductive annealing at 800[Formula: see text]C, meanwhile Sm–Co nanoparticles were formed at 850[Formula: see text]C. FESEM analysis revealed that the Sm–Co nanoparticles were composed in the form of spherical granules and exhibited well distribution with size in the range of 100 nm. The room temperature saturation magnetization and coercivity of the Sm–Co nanoparticles were 49.61 emu/g and 3.53 kOe, respectively.


2012 ◽  
Vol 724 ◽  
pp. 45-48 ◽  
Author(s):  
Woo Teck Kwon ◽  
Soo Ryong Kim ◽  
Y. Kim ◽  
Yoon Joo Lee ◽  
Ji Yeon Won ◽  
...  

β-SiC powder was synthesized using silicon sludge from photovoltaic silicon-wafer production by varying heat treatment temperature and carbon contents. The synthesized β-SiC powder and silicon sludge was analyzed by XRD, SEM, FT-IR and Particle size analysis. It is known that the conversion of SiC from the mixture of Silicon and Carbon is mainly affected by the mole ratio of C/Si and heat treatment temperature. In this study, the influence of reaction temperature and carbon contents on the synthesis of β-SiC from silicon sludge was examined.


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