共查询到19条相似文献,搜索用时 967 毫秒
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以尿素为沉淀剂,硝酸钇为钇源,十六烷基三甲基溴化铵为分散剂,采用均相沉淀法制备球形纳米氧化钇粉体,研究了反应物浓度比、表面活性剂用量、反应时间、搅拌转速、反应温度对氧化钇形貌及粒径的影响。通过激光粒度分析、X射线衍射(XRD)分析、扫描电镜(SEM)分析、傅里叶红外光谱(FTIR)分析等手段对样品进行表征。结果表明,反应物浓度比、反应时间、搅拌转速、反应温度会影响粉体的尺寸,适量CTAB的加入可显著降低氧化钇的粒径;在最佳工艺条件下,可制得粒径大小为110~130 nm的球形氧化钇粉体。 相似文献
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超细氧化钇合成与表征 总被引:2,自引:1,他引:1
以硝酸钇为原料,氨水、碳酸铵、酒石酸铵为沉淀剂,聚乙二醇、十二烷基苯磺酸钠、十六烷基三甲基溴化铵为表面活性剂,在水溶液中制备氧化钇前驱体,在空气中焙烧制备氧化钇粉体;用X射线衍射(XRD)、扫描电镜(SEM)、红外光谱(IR)对样品进行表征,用激光粒度仪分析样品的晶粒团聚度.结果表明,使用氨水、碳酸铵、酒酸铵为沉淀剂所得前驱体在673 K焙烧2 h,均获得立方晶相氧化钇粉体,一级晶粒直径分别为13,40,63 nm;用小分子有机醇回流处理氧化钇前驱体(氢氧化钇),团聚体粒径为58.8 nm,焙烧后的氧化钇团聚体粒径为423 nm,说明有机醇回流处理阻止了粒子团聚. 相似文献
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本研究以Zn和Se为源物质,NaOH水溶液为反应介质,采用水热法在100~200℃下水热反应12~36h制备了ZnSe粉体。采用正交试验方法,研究了各水热工艺条件对所制备ZnSe粉体粒径影响的显著性。采用XRD、XPS、EDAX和SEM等方法测试了所制备样品的相结构、表面元素状态、化学组成以及表面形貌,并研究了粉体的光学吸收特性。研究结果表明,所制备的粉体为立方闪锌矿型ZnSe,所制备的ZnSe粉体对紫外区的光呈现明显吸收,其光吸收边为454.0~458.3nm,并随晶粒尺寸的减小而呈现“蓝移”。 相似文献
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超细BaTiO3粉体制备的研究进展 总被引:3,自引:0,他引:3
综合评述了超细酸钡BaTiO3粉体制备目前采用的各种方法,包括共沉淀法、微乳液法、柠檬酸法、草酸盐法、水热法、溶液热合成法、Sol-gel法和金属有机物热解法和有机盐-氢氧化物法.评述了目前对先驱体溶液化学对溶胶的形成、溶胶凝胶转变、粉体的形成影响以及晶粒尺寸和粒子尺寸与粉体结构的关系. 相似文献
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Uniformly dispersed yttrium aluminum garnet (Y3Al5O12, YAG) ultrafine powders were synthesized by co-precipitating a mixed solution of aluminum and yttrium nitrates with ammonium hydrogen carbonate in the presence of sodium dodecyl sulfate (SDS) as dispersing agent. The primary purpose of introducing SDS was to protect YAG particles from agglomeration. The evolution of phase composition and micro-structure of the as-synthesized YAG powders were characterized by thermogravimetry/differential scanning calorimetry, X-ray diffraction, infrared spectra and scanning electron microscopy. The results showed that phase-pure YAG powders could be achieved by calcination of the precursor at 900 °C for 2 h. Uniformly dispersed YAG powders with a particle size of approximately 90-100 nm were obtained with optimum molar ratio of Al3+ to SDS at 2. And excessive SDS restrained good dispersion of the YAG powders. The dispersion mechanism of SDS in the preparation process was discussed. 相似文献
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Jin Zhao Jianwen Zhang Ming Xu Jianfeng Chen 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2005,110(1-3):19-29
Based on the population balance and mass balance in a reactive precipitation process, a numerical simulation model was developed to predict the particle size distribution (PSD) in the reactive precipitation process. The precipitation system of BaCl2 with Na2SO4 to prepare BaSO4 in aqueous solution was adopted to obtain ultrafine particles in a stirred precipitation reactor and the particle size distribution and the morphology of the particle were observed under transmission electron microscope. It was illustrated by the experimental observation of the micrographs of BaSO4 particles obtained that apparent agglomeration occurred between the particles, which phenomenon must be taken into consideration in PSD modeling. The population balance equation was calculated by discretization method to obtain particle number and particle size distribution. By implementing the model, the reactive precipitation process in a batch reactor including reaction, nucleation, growth and agglomeration was simulated. The simulation results were validated by the experimental data of BaSO4 precipitation. Further analysis was endeavored to explore the effects of some important factors such as the supersaturation degree and agglomeration on the evolution of the volume-based characteristic particle size and the variance of volume-based characteristic size of the particles. It was depicted that particle size and particle size distribution are controlled by the supersaturation degree and agglomeration between the particles. Stemming from the analysis in the context, the disciplinarian of the influences of these factors and the method for controlling particle size distribution were presented for the reactive precipitation process. 相似文献
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Wenbin Liu Wenxin ZhangJiang Li Huamin KouDi Zhang Yubai Pan 《Journal of the European Ceramic Society》2011,31(4):653-657
Neodymium doped yttrium aluminum garnet (Nd:YAG) ultrafine powders were synthesized by co-precipitation method using MgO as dopant. The addition of small amount of MgO can reduce the agglomeration and particle size of the produced Nd:YAG powders. The results show that pure phase YAG powders can be achieved by calcining of the precursors at 1000 °C for 2 h. The MgO doped Nd:YAG powders show better dispersion compared with the undoped powders. When the MgO content is 0.01 wt.%, well-dispersed Nd:YAG powders with spherical particles of 100 nm diameter were obtained. The transmission of the corresponding Nd:YAG ceramics is 82.6% at the wavelength of 1064 nm, which is comparable to Nd:YAG single crystals. 相似文献
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An innovative method for deagglomeration of ultrafine powders was developed in this paper. The method was based on electrohydraulic forces produced by electric breakdown discharge between two electrodes submerged in liquid. By controlling the process parameters (voltage, electrode separation and reaction time), PbTiO3 ultrafine powders with spherical, tabular and aciculate shape were successfully deagglomerated. Two ways based on centrifugal sedimentation and laser-light scattering were used to determine the particle size distribution. Scanning electron microscope (SEM) images showed that the agglomeration of PT powders was greatly reduced. 相似文献
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高纯超细SrTiO3粉料的液相合成方法 总被引:4,自引:0,他引:4
本文研究了三种高纯超细SrTiO3粉料的液相合成方法:草酸盐沉淀法、过氧化物热分解法和液相直接沉淀法。通过在使用原料、制备流程、工艺条件、粉料收率及粉料性能等方面的对比得出:液相直接沉淀法具有原料便宜易得、工艺流程简单、操作方便、不需高温热分解和粉料收率高等优点,而且制得的粉料在粒度、粒度分布、颗粒形状及团聚状态等方面均优于另外两种方法制备出的粉料。 相似文献
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氨水-草酸共沉淀法中试制备微米CeO2工艺的初步研究 总被引:1,自引:0,他引:1
以氨水-草酸为共沉淀剂对氯化铈进行了沉淀实验,研究了反应温度、物料浓度、搅拌强度、陈化时间等因素对草酸盐粒度的影响,确定了较佳反应条件:草酸共沉淀法,陈化时间60min,CeCl3浓度1mol· L-1,搅拌速度400r·min-1,反应时间3h,焙烧温度800℃,氨水-草酸pH为1~6,制备了微米级的氧化铈并进行了中... 相似文献
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以硝酸钇和硝酸钕为起始原料,分别以碳酸氢铵、尿素和草酸铵为沉淀剂,采用反滴的方式,通过控制滴定速度和PH值等条件,沉淀法制得前驱体粉料。前驱体经去离子水洗一无水已醇洗涤一去离子水洗可提高Y2O3粉体活洗。研究结果表明:选用不同沉淀剂,煅烧所得Y2O3粉末都跟标准的Y2O3粉末的XRD图谱吻合,只是由于结晶度的不同而表现出峰值强度的不同。不同沉淀剂对煅烧后所得Y2O3粉末的形貌影响显著。碳酸氢铵、草酸铵作为沉淀剂所得粉体的团聚现象较严重,颗粒之间产生部分烧结颈。所得粉体为片层状。尿素溶液作为沉淀剂时,粉体分散较好,但粒度分布很宽,有大颗粒存在,所得粉体接近球形。 相似文献
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多孔纳米SiO2微粉的制备与表征 总被引:11,自引:0,他引:11
多孔状纳米SiO2微粉的制备是以水玻璃和盐酸为原料,添加适宜的稳定剂(非离子表面活性剂)在适宜的pH值和温度下沉淀合成。要得到性能优良的SiO2纳米微粉,最佳工艺的研究尤其重要。用BDL-B型电位仪、BET、EPMA-电子探针及DTA-TGA等手段对其性能进行了表征,结果表明,制得的SiO2超细微粉,颗粒呈多孔状,具有巨大的比表面积,高达1000m2/g以上,孔径为25Å左右。粒度分布均匀,粒度可达纳米级,这种粉末具有特殊的性能。 相似文献