制备低团聚掺锑氧化锡超细粉体的新方法

以SnCl4·5H2O和SbCl3为原料,用醇盐水解法制备了纳米掺锑氧化锡(ATO)导电粉体。用正丁醇—二甲苯的混合溶剂共沸蒸馏、有机脱水剂以及其它方法对前驱体胶态沉淀进行脱水处理,以消除粉体团聚。运用XRD、TEM、BET等手段对粉体进行表征,比较了各种脱水处理方法对ATO纳米导电粉体的粒度、团聚度、晶粒生长以及电阻率的影响。结果表明,混合溶剂共沸蒸馏处理以及有机脱水剂是比较有效的脱水方法,可以用来制备比表面积大(85.32m2·g—)、团聚小、电阻率低1的纳米ATO导电粉体。     

纳米TiO2粉体制备过程中结晶度的控制

采用醇盐水解法，控制醇盐和水的摩尔比和水解的速度等条件，可以制备出５～２０ｕｍ左右的纳米氧化钛粉体．用乙醇洗涤以后，沉淀物转变为无定形；而在乙醇洗涤以前用醋酸处理过的粉体为晶体结构（锐钛矿结构）．不同的处理方法对二氧化钛粉体团聚的影响不同，ＸＲＤ、ＢＥＴ、ＤＴＡ－ＴＧ和ＴＥＭ的研究结果表明，在一定的条件下，经醋酸处理过的粉体表现出优良的性能，晶粒尺寸小，团聚度低，而且失重小，在较低的温度下就进行由锐钛矿向金红石的转变．粉体的这些性能直接影响到材料的烧结特性．     

纳米粉体干燥方法的研究

采用三种干燥方法：冷冻干燥，共沸蒸馏和烘箱干燥对溶胶－沉淀法制备的沉淀进行干燥处理，得到了立方相ＢａＴｉＯ３纳米粉，研究发现：冷冻干燥和共沸蒸馏都能防止粉体中形成硬团聚，提高了烧结活性，其中冷冻干燥法效果更有显，文章同时两种干燥方法防止硬团聚形成的机理进行了讨论。     

共沸蒸馏法合成CeO2纳米颗粒研究

分别以乙醇、正丙醇、异丙醇、正丁醇、异丁醇、仲丁醇及叔丁醇等七种有机醇作为共沸剂,采用液相沉淀法结合共沸蒸馏处理前驱体成功合成了分散性良好、粒子尺寸分布为10-20nm的纳米CeO2颗粒,运用TG／DTA、FI—IR、XRD、TEM等方法对不同有机醇的共沸蒸馏作用以及产品性能进行了分析和表征,探讨了共沸蒸馏法制备纳米CeO2的机理。结果表明：共沸蒸馏能起到有效脱除前驱体凝胶中的水分,防止其干燥和焙烧过程中的硬团聚形成的作用,其中七种醇中以正丁醇的共沸蒸馏效果最佳,所得纳米CeO2颗粒的粒度、均匀及分散性能最好。     

沉淀-共沸蒸馏法合成超细钴蓝颜料的研究

利用沉淀-共沸蒸馏法合成超细钴蓝颜料,并采用扫描电镜(SEM)、X射线衍射(XRD)、荧光反射仪现代分析测试技术对样品性能进行表征.结果表明,用正丁醇共沸蒸馏能有效防止干燥过程中颗粒间的团聚.经1000℃煅烧2h后的钴蓝粉体材料具有良好的分散性、结晶度高、外形规则.其蓝光波段反射率为67 %,红光波段反射率为13 %,达到彩色显象管用钴蓝颜料的要求.为实现性能优异、超细钴蓝的国产化提供了借鉴意义.     

共沸蒸馏法制备超细氧化铝粉体及其表征

用改进的溶胶－凝胶法（ｓｏｌ－ｇｅｌ）制备了单分散纳米级Ａｌ２Ｏ３粉体,研究了不同干燥方法对产品粒子性能的影响。结果表明,共沸蒸馏法能够有效地对氢吕凝胶脱水,防止了硬团聚体的形成,在１１５０℃的温度下煅烧,可制得尺寸分布均匀、呈球形的α－Ａｌ２Ｏ３超细粉体,其平均粒径为６８ｎｍ,以透射电镜（ＴＥＭ）、Ｘ射线衍射（ＸＲＤ）、热重（ＴＧ）、差热（ＤＴＡ）、比表面测定（ＢＥＴ）等手段对所得的超细Ａｌ２Ｏ     

乙酸异戊酯共沸干燥法制备低团聚掺锑氧化锡纳米微粉

以SnCl4·5H2O和SbCl3乙醇溶液为原料,用阴离子树脂交换除氯水解法制备得到无氯离子的前驱体掺锑氢氧化锡胶体沉淀。首次对以含氧官能团为主的系列憎水有机溶剂进行了共沸干燥脱水研究,并对所得粉体团聚程度进行比较。实验发现掺锑氧化锡共沸脱水干燥效果与有机溶剂分子结构之间有密切关系,提出了选择共沸有机溶剂的3个原则,在一系列有机溶剂中选择了最符合的乙酸异戊酯进行干燥实验,与常用的正丁醇共沸溶剂进行了消除粉体团聚效果的比较。运用IR、BET、TEM、XRD等方法对掺锑氢氧化锡粉体的结构、比表面积、形貌、物相进行表征。结果表明,乙酸异戊酯溶剂是理想的共沸干燥有机溶剂,其干燥所得掺锑氢氧化锡蓬松粉体的比表面积为284.44m2/g,比用正丁醇处理的增大了22%。将乙酸异戊酯干燥所得的掺锑氢氧化锡微粉经热处理后得到了低团聚的掺锑氧化锡纳米微粉。     

共沸蒸馏法制备单分散氧化镍微粉

先采用均匀沉淀法制得单分散的氧化镍前驱体粉末 ,然后用正丁醇进行共沸蒸馏脱水处理。经干燥、煅烧后成功地制成了单分散性相当好的氧化镍微粉。实验证明 ,共沸蒸馏能有效地脱除湿粉末中的水分 ,丁氧基取代了颗粒表面的羟基 ,从而防止了颗粒间Ni—O—Ni的形成 ,消除了硬团聚形成的可能性。     

无团聚ZrO2-HfO2-Y2O3复合纳米粉体的制备

以分析纯ZrOCl2·8H2O、HfOCl2·8H2O和Y(NO3)3·6H2O为原料,采用反向滴定共沉淀-共沸蒸馏法成功地制备出无团聚的ZrO2-HfO2-Y2O3复合纳米粉体.借助XRD、TEM、BET等手段分析了制备工艺对粉体粒径和团聚状态的影响.研究表明,分散剂PEG的加入量及前驱体湿凝胶的处理方式对最终制备的ZrO2-HfO2-Y2O3复合粉体的晶粒度影响不大,但显著影响粉体的分散状态.分散剂加入量为1%(质量分数)并对湿凝胶共沸蒸馏处理条件下最终获得的粉体的分散性最好.前驱体沉淀经500℃焙烧1h后,生成了具有高氧离子电导率的立方晶型ZrO2基ZrO2-HfO2-Y2O3固溶体,粉体的平均粒径约为15nm.     

无团聚纳米氧化锆的制备及应用

采用高分子表面修饰－共沸蒸馏工艺成功地制备了纳米氧化锆微粒;合成过程中高分子的空间位阻作用阻碍了前驱体颗粒的长大,通过与正丁醇的共沸蒸馏有效地脱除了前驱体内的水分,在颗粒表面形成了正丁醇分子的包裹结构,在随后的干燥过程中避免了颗粒间形成强化学键,获得了平均粒径在20nm的无团聚的纳米微粒,纳米氧化锆微粒加入到润滑脂中能明显改善后者的耐磨性能。     

Preparation of nanosized titania powder via the controlled hydrolysis of titanium alkoxide

By controlling the hydrolysis of titanium butoxide, followed with or without an ethanol washing process, the preparation of nanoscale titania powder was studied in detail. The characteristics of different powders produced by the direct precipitation (without an ethanol wash) and ethanol wash processes were studied by X-ray diffraction, transmission electron microscopy, BET, thermogravimetry and differential thermal analysis techniques. By comparison, it was found that both the direct precipitation and ethanol wash methods can obtain slightly agglomerated nanoscale titania powders of less than 15 nm, but the ethanol wash can further reduce the agglomeration. The particle sizes of titania powders can be modified while still retaining the anatase structure.     

Antibacterial and photocatalytic activity of ZnO nanoparticles from Zn(OH)2 dehydrated by azeotropic distillation,freeze drying,and ethanol washing

In this study, the antibacterial and photocatalytic activities of a series of ZnO nanoparticles (NPs) produced using different dehydration methods on as-prepared zinc hydroxide precipitates (Zn(OH)₂) have been investigated. Oven drying, azeotropic distillation, freeze drying, and ethanol washing methods were compared for their ability to yield non-agglomerated powders after precipitation synthesis. β-Zn(OH)₂ single phase was observed after ethanol washing, oven drying, and freeze drying procedures, while azeotropic distillation transformed β-Zn(OH)₂ into ZnO before calcination. Nanosized powders with high surface areas were produced via sublimation during the freeze drying process, and by replacement of hydroxyl groups on the precipitate surface with butoxy groups during azeotropic distillation. Both the photocatalytic degradation of Rhodamine B and the antibacterial activity against the pathogens Escherichia coli and Staphylococcus aureus were enhanced for dehydration methods that increased the surface area of ZnO NPs, suggesting that both photocatalytic and antibacterial behaviors were governed by similar mechanisms.     

共沉淀法制备Ce-TZP/Al2O3纳米复合粉的工艺研究

通过正交设计试验法研究了共沉淀法制备Ce TZP/Al2 O3纳米复合粉的工艺条件。结果表明 ,当混合溶液的浓度为 0 5M ,加入活性剂PEG及络合剂EDTA作为分散剂 ,溶胶的pH值为 8～ 9并采用醇洗 +共沸蒸溜进行脱水时 ,所得到的粉末粒径最小 ,分散性最好     

Fabrication of titanate nanowires with different dimensions

Titanate nanowires were fabricated by the reaction of titania particles in a highly concentrated KOH aqueous solution at 150 °C for more than 20 h followed by the rinsing of the resultant compound with a 0.1 M HCl aqueous solution and purified water. The diameter and length of the titanate nanowires can be controlled by using titania powders with different crystalline phases and particle sizes. The crystalline phase in the titanate nanowire was considered to be a hydrated titanate.     

The influence of different drying conditions on powder properties and processing characteristics

A water-based suspension of submicron titania particles was dried using a variety of techniques. The resulting powders were fully characterized in order to observe the effect of drying conditions on particle agglomeration. Direct evaporation methods led to quite severe agglomeration, whilst removal of the water by a freeze-drying technique produced powders containing only weak-secondary clusters.

The consequences of the state of aggregation after drying on powder compaction, sintering rates and microstructural development were determined. Although all powders originated from a common starting suspension, samples isolated by freeze drying sintered most rapidly, reaching about 98% of the theoretical density after firing at 1150 °C for 2 h. Agglomerated powders obtained after drying by evaporation, using either a heat lamp or microwave oven to drive off the water, required twice as long to sinter to comparable density. Moreover there was evidence of a much finer-grained microstructure in ceramics fabricated from freeze-dried products.     

钙热还原法制备钛粉过程的研究

以颜料级TiO2、分析纯无水CaCl2和金属钙为原料,探索一种真空钙热还原制备金属钛粉的新方法,并借助XRD,SEM/EDS等设备对产物成分和钛粉进行表征。结果表明,添加的CaCl2可有效地减弱烧结影响并增大了气-固反应界面有助于还原反应。当CaCl2与TiO2比例为1∶4时,片状原料在1000℃下和钙蒸气充分反应6h,还原产物酸洗干燥后制备出低杂质含量的钛粉。粒度分布在10～20μm之间,粉末颗粒呈不规则形状,分布均匀且无大块团聚现象。