共查询到19条相似文献,搜索用时 64 毫秒
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喷雾热解制备稀土超细粉末(Ⅰ):氧化钇粒子形态与形成机理 总被引:1,自引:0,他引:1
对Y(NO3)3.6H2O的差热和热重分析表明,Y(NO3)3.6H2O经脱水和热分解在580℃以上完全分解为Y2O3,在此基础上,以Y(NO3)3.6H2O为前驱体,采用喷雾热解过程制备出粒度为0.50-1.50μm的立方相球形Y2O3粉末。 相似文献
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直接沉淀法制备ZnO超细粉末及其性质测定 总被引:1,自引:0,他引:1
用直接沉淀法制备ZnO超细粉末,利用激光散射测定其粒径,与其比表面积的大小作对比。利用红外光谱(IR)、X-射线衍射(XRD)、差热分析(DTA)对ZnO超细粉末进行分析。确定了最佳的制备工艺条件。 相似文献
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湿化学法制备超细粉末过程中的团聚机理及消除方法 总被引:56,自引:0,他引:56
超细粉末由于具有独特的物理和化学特性,已经被广泛应用于各行各业之中。开发制备超细粉末的方法越来越多,其中湿化学法制备超细粉末具有显著的优点:原料成本低,设备、工艺简单,生产的粉末纯度高、粒度小,粉度分布范围窄,粒度组成可控性好。但是湿化学法制备粉末过... 相似文献
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用研磨抛光的方法制备了Φ0.1mm的Pt微盘电极(研磨微电极)。用这种研磨微电极研究强碱性溶液中Bi2O3的循环伏安行为时,通过SEM形貌分析和Bi元素X射线能谱分析,认为这种电极具有较高的稳定性。使用这种微电极对常粒Bi2O3、纳米Bi2O3进行了循环伏安研究。结果表明纳米Bi2O3比常粒Bi2O3具有更高的电化学活性。说明研磨微电极可以较好地应用于某些粉末材料的电化学研究中。 相似文献
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超低碳含量超细Bi系超导体原始粉末的制备毛传斌*周廉杜泽华(东北大学材料学工程系沈阳110006)(西北有色金属研究院超导材料研究所宝鸡721014)1引言粉末套管法制备的银包套(Bi,Pb)2Sr2Ca2Cu3Ox(2223)超导带材(Ag/Bi(... 相似文献
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冰冻升华极稀溶液制备的iPS超细粉末结晶的结构与性质 总被引:2,自引:0,他引:2
高分子在浓度低于动态接触浓度cs的极稀溶液中以单链形式存在[1,2],用冰冻升华法将极稀溶液中的溶剂除掉可获得高分子的超细粉末.这些超细粒子与普通的聚合物相比,比表面积大,高分子链之间缠结程度小,有可能表现出特殊的物理性质.本文用示差扫描量热计(DS... 相似文献
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以甲醛作还原剂制备超细铜粉 总被引:13,自引:0,他引:13
以甲醛作还原剂制备超细铜粉刘志杰,赵斌,张宗涛,胡黎明(华东理工大学化学系,上海200237)(华东理工大学国家超细粉末工程研究中心)超细铜粉已得到广泛应用,不同粒径的铜粉有不同的用途:应用于电学领域的铜粉大部分是微米级铜粉[1];纳米级铜超微粒子分... 相似文献
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Ultrafine gamma ferric oxide has been prepared by controlled heating of ferrous oxalate at a temperature range of 225° to 300°C in moist air. Ferrous oxalate was prepared both in aqueous as well as in Aerosol OT microemulsion systems. It has been observed that the product is always a mixture of alpha and gamma ferric oxides which were characterized by TGA, DTA and XRD studies. Microemulsion mediated ferrous oxalate was found to yield more gamma ferric oxide than that from ferrous oxalate prepared in aqueous solution. However, the yield of gamma ferric oxide prepared through microemulsion mediated system depends on the size of the microemulsion droplets in which precursors have been participated as well as calcination temperature. 相似文献
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喷雾-胶凝法制备超细莫来石粉末 总被引:5,自引:0,他引:5
以水玻璃和硝酸铝为原料 ,通过喷雾 -胶凝法和共沸蒸馏技术制备莫来石前驱粉体 ,然后煅烧得到超细莫来石粉末 .用TG -DTA、XRD、TEM及BET研究了莫来石前驱粉体在煅烧过程中的热学性质、物相与比表面变化及颗粒大小与形貌变化 ,并对所制得的莫来石粉进行了表征 .结果表明 ,莫来石前驱粉体经 130 0℃煅烧 1h可制得粒径为 2 5nm~ 4 0nm ,比表面积为 4 2 5m2 /g的莫来石超细粉 ;煅烧过程中的物相变化次序为 :勃姆石 +非晶态SiO2 →非晶态Al2 O3 +非晶态SiO2 →γ -Al2 O3 +非晶态SiO2 → 3Al2 O3 ·2SiO2 . 相似文献
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Liana Marta Lelia Ciontea T. Petrisor Maria Zaharescu D. Crisan Iovanca Haiduc 《Journal of Sol-Gel Science and Technology》1994,2(1-3):437-441
Bismuth high T
c superconducting oxide compounds were obtained by sol-gel method using acetate precursors. A study of the decomposition of quasi-amorphous acetates has been carried out to establish the conditions of superconducting phase formation. A comparison of the acetate sol-gel route with the oxalate coprecipitation method (previously used by the authors) reveals comparable results. Both methods require much shorter periods of thermal treatment for the formation of superconducting phases, as compared with the solid state reactions. The sol-gel route leads to better results from this point of view. 相似文献
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水热法合成纳米氧化铜粉体及其性能表征 总被引:14,自引:1,他引:14
氧化铜粉体广泛用于电极材料[1 ] 、玻璃、催化剂 (载体 )等领域。粒子的超细化 ,可以显著的改善氧化铜的应用性能。制备纳米氧化铜的方法有固相合成法[2 ] 、沉淀转化法[3] 和络合沉淀法[4] 。本文采用水热法一步合成了纳米氧化铜粉体 ,所得粉体粒度均匀 ,操作简便 ,易于工业化生产。1 实验部分1 1 样品制备将硝酸铜 (分析纯 ,北京化工二厂 )配成浓度为 1 .0mol·L- 1 的溶液 ,按物质的量比为 2∶1加入浓度为 1 .0mol·L- 1 的尿素 (分析纯 ,上海试剂一厂 )溶液 ,然后在 95℃~ 1 2 5℃下加热溶液进行反应。由于水溶液在 1 0 0… 相似文献
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Poly (vinyl acetate) (PVAc) loaded bismuth oxide (Bi2O3) nanorods were successfully prepared at ambient pressure. X‐ray diffraction (XRD) and transmission electron microscopy were used to characterize the final product. It was found that Bi2O3 nanorods were formed and the diameter of the rods was confined to about 8 nm. The diameter and length of formed rods were found to increase by increasing the bismuth oxide concentration in the PVAc matrix. The optical properties of the nanocomposite films were characterized from the analysis of the experimentally recorded transmittance and reflectance data in the spectral wavelength range of 300–800 nm. The values of some important parameters of the studied films are determined such as refractive index (n), extinction coefficient (k), optical absorption coefficient (α), and band energy gap (Eg). According to the analysis of dispersion curves, it has been found that the dispersion data obeyed the single oscillator of the Wemple–DiDomenico model, from which the dispersion parameters and high‐frequency dielectric constant were determined. In such work, from the transmission spectra, the dielectric constant (ε∞) and the third‐order optical nonlinear susceptibility χ(3) were determined. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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电化学电容器电极材料超细MnO2的制备及表征 总被引:10,自引:0,他引:10
高性能的电化学电容器具有极其重要和广阔的应用前景(1)。以RuO2等贵重金属氧化物为电极材料的电化学电容器已应用于多个领域(2),但昂贵的价格限制了它们更加广泛的应用。有些廉价金属氧化物也具有一定的氧化还原准电容,如Co3O4、NiO和MnO2等(1,3 6)。二氧化锰价格低廉,资源丰富,电化学性能好,其作为电化学电容器的活性材料具有更大的应用前景和价值。本文采用K2S2O8氧化MnSO4·H2O制得超细MnO2,并通过XRD、TEM和SEM测试对其进行表征,并研究了其在0 5mol/LNa2SO4水溶液中的循环伏安性能、恒流充放性能以及电容稳定性能。1… 相似文献
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Wen Zhu Junyou Yang Xianhui Gao Jie Hou Siqian Bao Xian Fan 《Frontiers of Chemistry in China》2007,2(1):102-106
Thin-layer electrochemical studies of the underpotential deposition (UPD) of Bi and Te on cold rolled silver substrate have
been performed. The voltammetric analysis of underpotential shift demonstrates that the initial Te UPD on Bi-covered Ag and
Bi UPD on Te-covered Ag fitted UPD dynamics mechanism. A thin film of bismuth telluride was formed by alternately depositing
Te and Bi via an automated flow deposition system. X-ray diffraction indicated the deposits of Bi2Te3. Energy Dispersive X-ray Detector quantitative analysis gave a 2: 3 stoichiometric ratio of Bi to Te, which was consistent
with X-ray Diffraction results. Electron probe microanalysis of the deposits showed a network structure that results from
the surface defects of the cold rolled Ag substrate and the lattice mismatch between substrate and deposit.
Translated from Chinese Journal of Applied Chemistry, 2005, 22 (11) (in Chinese) 相似文献
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超细银粉在太阳能电池正面电极领域有广阔的应用前景,其粒径分布、分散性、表面态与其性能息息相关。 本文通过在液相还原法合成超细银粉的后期引入氧化石墨烯(GO),利用溶液状态下二者相对活性的表面的相互作用获得了性能优良的银粉。 通过X射线衍射(XRD)、拉曼光谱(Raman)和扫描电子显微镜(SEM)等手段对所得复合超细银粉进行结构及形貌表征,结果显示该法获得的银粉分散性较好、尺寸分布较窄。 进而,利用紫外-可见光谱探讨了GO与银粒子之间的相互作用。 而且研究发现:固定硝酸银溶液的浓度,随着GO含量的增加,银粉的导电性能先升高后降低,当GO的质量分数为2.5%时,导电性能更好。 这为超细银粉在实际中的应用提供重要数据和有益参考。 相似文献