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Preparation of Nano-Sized BaTiO3 Powders
Author: WuLinLin
Tutor: LiuXiaoLin
School: Beijing University of Chemical Technology
Course: Chemical Engineering
Keywords: Barium Titanate Two-step precipitation Sonochemistry Solvothermal Dielectric properties
CLC: TB383.1
Type: Master's thesis
Year: 2008
Downloads: 152
Quote: 2
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Abstract
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In this paper, TiCl 4 , Ba (OH) 2.8 H 2 O, NH 3 · H 2 O and NaOH as raw materials , ethanol and water mixture as the solvent , respectively, using the two - stage precipitation method , ultrasonic chemical method and solvothermal prepared under relatively mild conditions , the particle diameter of 14 ~ 160nm , the cubic phase of BaTiO 3 < / sub> powder , a systematic study of the three methods of process parameters and the performance of the resulting powder was characterized . The two-step precipitation method , prepared at 75 ℃ the BaTiO particle size of approximately 17nm 3 sub > powder . Forming BaTiO 3 nuclei desired temperature is higher than 60 ° C , to increase the concentration of the reactants is conducive to the formation of crystals ; little change of the particle diameter of the powder is formed within 60 ~ 80 ℃ ; reaction time is greater than the 0.5h able crystallized BaTiO 3 and increases slightly with time the powder particle size . Sonochemical method , 14 ~ 60nm and particle morphology was spherical BaTiO 3 sub > powder prepared at 75 ℃ . Ultrasonic intensity had a significant effect on the powder particle size , sound intensity and the greater the powder particle size greater ; , ultrasonic and mechanical stirring introduction can change the particle diameter of the final powder , while the particle distribution is uniform and good dispersion . Solvothermal Ti 4 sup> , when the reactant concentration of 0.1mol / L, Ba / Ti molar ratio of 1.6:1, the concentration of mineralizing agent for 2mol / L , can be obtained at 200 ℃ the particle size of approximately 70nm square BaTiO 3 sub > powder . Improve with hydrothermal time and the concentration of reactants , the powder particle size gradually increases. Thermal analysis method to determine BaTiO 3 ceramic sintering temperature of 1150 to 1250 ° C , using a two step sintering method BaTiO 3 powder sintering to obtain a porcelain body density of up to 98.9%, room temperature, a dielectric constant of 3834 , corresponding to the dielectric loss of 0.037 .
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