Papers by Keyword: Chemical Coprecipitation

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Authors: R. Bolsoni, Valderes Drago, E. Lima Jr
Authors: Pei Xin Zhang, Mu Chong Lin, Qiu Hua Yuan, Zhen Zhen Fan, Xiang Zhong Ren, Dong Yun Zhang
Abstract: With the acetates of nickel, manganese and cobalt as raw materials and lithium hydroxide as precipitation agent, the precursor Ni1 / 3 Co1 / 3 Mn1 / 3 (OH) 2 was first prepared by chemical coprecipitation method, which was then mixed and ballmilled with certain stoichiometric ratios of LiOH∙H2O, and ultimately obtained LiCo1/3Mn1/3Ni1/3O2 after calcination process. Single-factor experiment method, in conjunction with XRD, SEM, and charge-discharge test, was utilized to study the influence of various factors, including the dispersion way of precursor, pH value of reaction solution, and the content of ballmilling lithium on the electrochemical properties of LiCo1/3Mn1/3Ni1/3O2. The results indicated that: (1) the material dispersed by ultrasonic treatment revealed excellent cycling performance, its ratio of capacity fading decreased at least 34.1% compared to those without ultrasonic process; (2) the optimum conditions of fabricating LiCo1/3Mn1/3Ni1/3O2 may be summarized as the treatment of ultrasonic dispersion, suitable pH value (12~13) and stoichiometric ratio (1.0) of ballmilling lithium.
Authors: Xiao Lin Liu, Xiao Liang Dou, Huan Ying Xie, Jian Feng Chen
Abstract: Bismuth ferrite (BFO), one of very few multiferroics with simultaneous coexistence of ferroelectric and magnetic ordering, has attracted much attention due to its potential applications for new memory devices. In this work, 30~90 nm BFO powders with single rhombohedral phase were prepared by chemical coprecipitation method and after calcining of 500oC. Photocatalytic properties of the powders and dielectric properties of BFO ceramic were characterized, respectively. Cut-off wavelength of the powders at 590 nm exhibited efficient ultraviolet photocatalytic activity, which has been demonstrated by a photocatalytic result. 0.3g BFO powders can make 10 ppm RhB aqueous solution (100 ml) to decolorize and RhB decomposition rate reached to 95% during 3 hr UV irradiation. BFO ceramic can be obtained by sintering the green disc compacted with BFO powders at 800oC for 1h. Its dielectric constant is t about 250, and its dielectric loss is 0.03 at below 100 oC in the frequency range of 102 ~ 104 Hz and up to 1200 at 200 oC under 1 kHz, respectively. Reduced polarization is found due to higher loss and lower dielectric constant of the ceramic when the measuing frequency is more than 104 Hz. Magnetic hysteresis loop of BFO ceramic also shows weaker magnetic property, which may be attributed to size confinement effect of the nanostructures.
Authors: S.A. Palomares-Sánchez, S. Ponce-Castañeda, M. Mirabal-García, L. Narváez-Hernández, R. de Lira-Hueso, O. Pérez-Orta, A. Huanosta-Tera, S. Díaz-Castañón
Authors: Ming Yu Zhang, Li Ping Wang, Qi Zhong Huang
Abstract: ITO (indium tin oxide) film of a high transmittance and high conductivity has been extensively studied because of its applications in optoelectronics. In this study, ITO nano-powder was prepared by constant pH chemical coprecipitation method. The experimental results show the precursor of the powders play a key role. The optimum was selected with orthogonal experiments. The optimum showed pH 8.5, temperature 60 °C, solution of indium and tin adding speed 100 mL/min, stirring rate 500rpm, additives 25 mg/L. the primary particle size is less than 10 nm with narrow distribution and good decentralization. SEM shows that particles are sphere-like and XRD shows that precursor consist of indium hydroxide and amorphous body. Zeta potential showed the powder is in nanoscale with uniformly dispersiveness. ITO nanocrystalline powder was formed after sintering at 600°C.
Authors: Shang Yue Shen, Rui Yang, Qiang Shen, Chuan Bin Wang, Lian Meng Zhang
Abstract: Al2(1-x)MgxTi1+xO5(x=0.05-0.3) composite powder was prepared by the method of chemical coprecipitation and subsequent sintering using TiCl4, MgCl2 and AlCl3 solution as the raw materials, and ammonia and ammonium carbonate as the solvent. Thermal dynamics and kinetic dynamics analysis of the precursor during the heat treatment were explored in detail, and the reaction process of Al2(1-x)MgxTi1+xO5 (x=0.3) composite powder was confirmed. Results show that, as the temperature increases MgO reacts with TiO2 of anatase phase to form MgTi2O5. At about 650°C, anatase transfers into rutile. Then MgTi2O5 reacts with Al2O3 to produce MgAl2O4 at 900°C. When the temperature is above 1100°C, the desired Al2(1-x)MgxTi1+xO5(x=0.3) composite powder is synthesized by the reaction of MgAl2O4, Al2O3 and TiO2 of rutile phase.
Authors: Jian Peng Zou
Abstract: With chemical coprecipitation method, high purity hydroxyapatite was successfully prepared in this paper. The microstructure and components of HA were characterized by XRD, SEM, FTIR, atomic emission spectrum and particle size analyzer. The results demonstrate that synthesized HA is very pure and is harmless to human body. Average particle size of HA powder is about 10.4μm. Crystallization degree of hydroxyapatite increases with the increase of sintering temperature and the optimal preparing technique is sintering at 750 for 2h with temperature-rising rate of 5°C·min-1. Grain growing activation energy of HA can be calculated as 24.8 kJ·mol-1 according to the relationship between grain size and sintering temperature. HA’s grain growth mechanism is interfacial diffusion controlling mechanism.
Authors: Chang Shu Tsai, Hong Yi Chen, Kwo Ping Chang
Abstract: Magnetic nano-particles are extensively studied in tumor therapy, target drug, gene screen, cell separation and magnetic resonance imaging study, due to theirs unique features such as its superparamagnetism, high saturation magnetization and high effective surface areas, etc. The aim of this work is to emphasize on the preparation and characterization of Fe3O4 magnetic nano-particles and its applications in hyperthermia . As the results, the Fe3O4 magnetic nanoparticle in this work has shown good qualities as well as in the literatures. It may be feasible to utilize in the field of hyperthermia.
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