Determination of Heat Treatment Temperature for Completing Polycondensation of Vinyl Substituted Silica Particles Prepared by Sol-Gel Method

2012 ◽  
Vol 35 (12) ◽  
pp. 2155-2160 ◽  
Author(s):  
K. M. Ashraf ◽  
S. Matsumoto ◽  
K. Kurumada
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.


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.


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.


2004 ◽  
Vol 19 (2) ◽  
pp. 667-675 ◽  
Author(s):  
Noriyuki Wada ◽  
Michiyo Kubo ◽  
Nobuko Maeda ◽  
Maegawa Akira ◽  
Kazuo Kojima

Ta2O5–xEr2O3 (TE) films were produced by a sol-gel method and a dip-coating technique with heat treatment at 600–1000 °C. Their powders were also prepared from the same sol. The Er3+ fluorescence property of the TE films containing various contents of Er3+ was measured as a function of the heat-treatment temperature. In crystallized films, the Er3+ fluorescence was observed because water-related residues (Ta–OH and H2O) and carbon-related residues (–CH3, –CH2–, –(C ⁼ O)–, and C≡C–H) were removed from the films. It is shown from infrared absorption spectroscopy that Ta–O− and Ta ⁼ O structures dissolve the Er3+ ions selectively and play a role in dispersing the Er3+. The strongest Er3+ fluorescence is observed in the TE film with 2 mol% of Er2O3 because of its highest ability to disperse the Er3+ ions.


2000 ◽  
Vol 613 ◽  
Author(s):  
Sun Hyuk Bae ◽  
Jae-Hyun So ◽  
Seung-Man Yang ◽  
Do Hyun Kim

ABSTRACTSilica slurry used as abrasives in wafer polishing process is made by dispersing silica particles in an alkali solution. Since commercially available colloidal or fumed silica particles need some modifications to be directly used as abrasive slurry due to their small sizes, irregular shapes or broad size distribution, we have prepared silica abrasives by particle growth of fumed silica or colloidal silica as seeds by sol-gel method. Silica slurries prepared by this step-wise growth from commercial seeds were tested using one-armed polisher for the comparison with commercial slurries and showed the performance comparable to commercial slurries. Microstructures of polishing slurries were investigated using transmission electron microscopy and ARES rheometer. From the result, stability of the slurry was found to be more important than the primary particle sizes for the polishing performance.


Silicon ◽  
2020 ◽  
Author(s):  
Xijia Zhao ◽  
Yihan Wang ◽  
Jianhui Luo ◽  
Pingmei Wang ◽  
Peiwen Xiao ◽  
...  

2010 ◽  
Vol 105-106 ◽  
pp. 123-125 ◽  
Author(s):  
Yong Li ◽  
Qi Hong Wei ◽  
Ling Li ◽  
Chong Hai Wang ◽  
Xiao Li Zhang ◽  
...  

In this paper, negative thermal expansion coefficient eucryptite powders were prepared by sol-gel method using silica-sol as starting material. The raw blocks were obtained by dry pressing process after the powder was synthesized, and then the raw blocks were heat-treated at 600º, 1150º, 1280º, 1380º, 1420º and 1450°C, respectively. Variations of density, porosity and thermal expansion coefficient at different heat treatment temperatures were investigated. Phase transformation and fracture surface morphology of eucryptite heat-treated at different temperatures, respectively, were observed by XRD and SEM. The results indicate that, with the increasing heat- treatment temperature, the grain size and the bending strength increased, porosity decreased, thermal expansion coefficient decreased continuously. Negative thermal expansion coefficient of -5.3162×10-6~-7.4413×10-6 (0~800°C) was obtained. But when the heat-treatment temperature was more than 1420°C, porosity began to increase, bending strength began to decrease, which were the symbols of over-burning, while the main crystal phase didn’t change.


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