直流电弧等离子体制备SnO2纳米粉末的研究

利用直流电弧等离子本蒸发-凝聚法制备SnO2纳米粒子，研究了SnO2粒子在等离子体焰流中的形成和生长机理，探讨了等离子体发生器功率、气体配比和冷却介质对SnO2纳米粒子粒度和纯度的影响，制备出了纯度大于98．8％、粒度可控的SnO2纳米粉末，为制造高性能SnO2气敏传感器打下了良好的基础。     

溶胶-凝胶法制备纳米TiO2/SnO2复合微粒的研究

以有机、无机盐为原料，通过加入稳定剂、催化剂，采用溶胶-凝胶法制备TiO2、SnO2、TiO2／SnO2纳米微粒，采用XRD、SEM和XPS等技术对粒子性能进行分析．结果表明：TiO2／SnO2粒子主要由锐钛矿型TiO2和金红石型SnO2组成，与纯TiO2、SnO2相比，TiO2／SnO2微粒的粒度小，分布均匀，不团聚。     

纳米Ag-Al2O3复合粉末的制备

用甲醛—银氨溶液,在超声波辐照下对10～20nm的A12O2粉末进行化学镀银,制备出了纳米Ag—A12O2复合粉末,并探讨了镀液组成及其工艺条件对纳米A12O2粉末化学镀银的影响。结果表明,改变镀液中氨水的含量和pH值可以控制镀液的稳定性和反应诱导期的长短;增重测定和X射线衍射分析结果表明,调整甲醛的用量和装载量的大小可以得到重量百分比为11％～74％银的纳米Ag—A12O2复合粉末。TEM观察的结果表明,通过该工艺所得到的Ag—A12O2复合粉末具有很好的均匀性。     

SnO2及SnO2／Fe2O3复合微米材料的合成及表征

本文首先以SnCl2·2H2O为主要原料,无水乙醇为溶剂,利用溶剂热法于180℃反应24h得到了SnO2微球;再以所制备的SnO2微球为前驱体,FeCl3·6H2O为主要原料,通过水热法得到SnO2／Fe2O3复合材料．利用X射线粉末衍射仪（XRD）和扫描电子显微镜（SEM）对所得产物进行了表征．结果表明：所得的SnO2为四方锡石型,形貌为微球,平均直径约为2．0μm;复合后得到的SnO2／Fe2O3微球平均直径约为2．5μm．其中,Fe2O3为六方赤铁矿型,在复合物的表面以小颗粒的形式存在,尺寸约为200nm．另外,也对SnO3与SnO2／Fe2O3微球的形成过程进行了讨论．     

机械化学法合成二氧化锡纳米晶

采用机械化学法,以SnCl2、Na2CO3为反应物,以NaCl为稀释剂合成SnO2纳米晶,采用TEM、XRD等方法对制备的SnO2纳米晶进行表征,并分析了球磨时间、稀释剂的用量及热处理温度对SnO2纳米晶晶粒尺寸的影响．研究结果表明增加球磨时间和稀释剂的用量可以有效降低SnO2纳米晶的晶粒尺寸,利用该法制备的SnO2纳米晶粒径均匀,较优条件下晶粒尺寸可达7 nm．     

复合隐身用超细粉体材料的制备工艺研究

以钛酸丁酯、醋酸钡、无水乙醇和冰醋酸为原料,通过溶胶-凝胶法制备了Ti/Ba比为1:1的纳米Ba-TiO3粉体;以分析纯In2O3和自制SnO2为原料,通过高温固相法制备ITO颜料粉末。采用多种胶粘剂,将纳米吸波剂BaTiO3粉体与ITO颜料粉末经超声分散后复合到玻璃基片上获得复合涂层样品。对粉体材料和涂层样品的工艺影响因素进行了系统研究。     

粉末Tb0.27Dy0.73Fe2的最佳磁粉粒度研究

从磁场取向和铁磁体磁化出发，研究了粉末Tb0.27Dy0.73Fe2的最佳磁粉粒度．计算结果表明：Tb0.27Dy0.73Fe2磁粉颗粒的单畴临界直径为22nm，磁粉粒度小于22nm时整个颗粒为单畴结构；磁粉粒度大于22nm时，磁粉将过渡到多畴结构．所以理论上粉末Tb0.27Dy0.73Fe2的最佳磁粉粒度为纳米数量级．理论值与实验值的偏离，主要是因为细颗粒磁粉比粗颗粒磁粉更容易氧化且细颗粒的浸润性较差．     

共沉淀法制备掺锑SnO2纳米级粉体

用共沉淀法 ,以SnCl4 ·5H2 O和SbCl3为原料 ,NH3·H2 O为沉淀剂 ,得到了掺锑SnO2 纳米级粉体。运用DSC -TG、XRD和UV等观测手段对微粉末进行了表征 ,考察了制粉条件对粉末晶粒平均尺寸、粉末电阻和粉末颜色的影响 ,探讨了影响机理     

微乳液法制备纳米ZnO粉体

采用双微乳液混合法制备纳米ZnO粉末．通过实验从nH2O／nAEO3 AEO9、反应物浓度、老化温度及时间、前驱体煅烧温度及时间等方面讨论影响产物的粒径，确定了制备纳米ZnO粉末的较理想的工艺条件．经XRD，TEM和激光粒度仪等检测表征，产物为球形六角晶系结构，平均粒径27nm，粒径尺寸分布范围较窄，99％颗粒达纳米级．     

静电纺丝技术制备Y2O3纳米纤维

采用静电纺丝技术制备了PVA/Y(NO3)3复合纳米纤维,研究了反应体系的最佳组成,系统地讨论了静电纺丝工艺的影响,获得了最佳制备条件。将PVA/Y(NO3)3复合纳米纤维在600℃焙烧10h,获得了晶态的Y2O3纳米纤维。XRD分析表明,PVA/Y(NO3)3复合纤维为无定型,Y2O3纳米纤维属于体心立方晶系,空间群为Ia3。SEM分析表明,PVA/Y(NO3)3复合纳米纤维表面光滑,平均直径约为110nm;Y2O3纳米纤维的直径约为50nm。该技术可以用来制备其他稀土氧化物纳米纤维。     

反应合成AgSnO2电接触材料的电学性能研究

本研究采用了一种新的制备工艺（反应合成法）制备AgSnO2（10）电接触材料，目的是解决SnO2颗粒与基体Ag的界面结合问题，对AgSnO2（10）进行了电阻率和电寿命方面研究，分析了电弧侵蚀后触点表面的形貌。结果表明：反应合成法制备的AgSnO2（10）材料具有接触电阻低、电接触寿命高等特点。电学性能方面优于传统粉末冶金制备的AgSnO2（10）和AgCdO（12）材料。     

液相法制备纳米钯粉的工艺研究

采用液相法,以Pd粉为原料,分别用HCHO,HCOOM,C2H4H2O作还原剂,把钯还原成纳米粉末。通过控制反应体系的pH值、浓度、温度及还原剂的种类和还原时间来控制粉末的粒径大小及其分布.实验结果表明:利用本法制备的Pd粉粒径在9 nm~20 nm,粒度分布均匀而且重现性好,适用于制造钯银导体浆料.     

Aqueous Sn-S Complex Derived Electron Selective Layer for Perovskite Solar Cells

A novel aqueous Sn-S complex solution was applied as precursor to fabricate SnO_2 electron selective layers (ESLs) for the hybrid perovskite solar cells (PSCs).The tin and sulfur powder were directly dissolved in a (NH_4)_2S water solution to form Sn-S precursor.After depositon and annealing,the SnO_2 film was formed,presenting as a low cost and enviromental friendly method for preparation of ESL.The films showed excellent transmittance at visible wavelength range.Moreover,the method exhibited high compatibility for doping using Cu,Cd,Li,and Zn elements.Zn doping (0.05 M) in the as-prepared SnO_2 ESL significantly improved perovskite solar cells (PSCs) performance.The highest PCE of 13.17% was achived with 15% enhancement compared to that of undoped SnO_2 ESL samples.TiCl_4 modifications on SnO_2 film improved photovoltaic performance to 14.45%,but resulted in the poor long-term stability,around 80% more degredation than that of PSCs based on Zn-doped SnO_2 films.     

Fabrication and characterization of nano silver powder prepared by spray pyrolysis

Silver powder was fabricated by spray pyrolysis, using 2%–20% AgNO₃ solution, 336–500 mL/h flux of AgNO₃ solution, 0.28–0.32 MPa flux of carrier gas and in the 620–820 °C temperature range. The effects of furnace set temperature, concentration of AgNO₃ aqueous solution, flux of AgNO₃ aqueous solution as well as carrier gas on the morphology and particle size distribution of silver powder, were investigated. The experimental results showed that with the high concentration of AgNO₃ aqueous solution, the average grain size of silver decreased with the increasing of furnace set temperature. But the gain size distribution was not homogenous, the discontinuous grain growth occurred. With the low concentration of AgNO₃ aqueous solution, the higher furnace set temperature made the nano sliver grains sintered together to grow. Nano silver powder about 100 nm was fabricated by spray pyrolysis, using 2wt% AgNO₃ solutions, 336 mL/h flux of AgNO₃ aqueous solution, 0.32 MPa flux of carrier gas at 720 °C furnace set temperature.     

Acid/base treatment of monolithic activated carbon for coating silver with tunable morphology

Silver coatings on the exterior surface of monolithic activated carbon (MAC) with different morphology were prepared by directly immersing MAC into [Ag(NH₃)₂]NO₃ solution. Acid and base treatments were employed to modify the surface oxygenic groups of MAC, respectively. The MACs’ Brunauer-Emmett-Teller (BET) surface area, surface groups, and silver coating morphology were characterized by N₂ adsorption, elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), respectively. The coating morphology was found to be closely related to the surface area and surface functional groups of MAC. For a raw MAC which contained a variety of oxygenic groups, HNO₃ treatment enhanced the relative amount of highly oxidized groups such as carboxyl and carbonates, which disfavored the deposition of silver particles. By contrast, NaOH treatment significantly improved the amount of carbonyl groups, which in turn improved the deposition amount of silver. Importantly, lamella silver was produced on raw MAC while NaOH treatment resulted in granular particles because of the capping effect of carbonyl groups. At appropriate [Ag(NH₃)₂]NO₃ concentrations, silver nanoparticles smaller than 100 nm were homogeneously dispersed on NaOH-treated MAC. The successful tuning of the size and morphology of silver coatings on MAC is promising for novel applications in air purification and for antibacterial or aesthetic purposes.     

二氧化锡(SnO2)纳米颗粒的水热合成及表征

采用柠檬酸钠辅助水热技术合成单分散的二氧化锡（SnO2）纳米颗粒,用X射线衍射（XRD）、场发射扫描电镜（FESEM）、紫外/可见光谱等手段对其结构、形态和光吸收性能进行了表征,XRD和FESEM结果表明该产物是正方结构的SnO2纳米颗粒,直径约为60 nm,并用吸收光谱估计了禁带宽度（约3.6eV）.     

一种制备纳米银粉的新方法

研究了一种通过树脂吸附-化学还原的方法制备纳米银粉的新方法．在硝酸银溶液中，使用PVP作保护剂、水合肼作还原剂制备纳米银粉过程中，加入LSC-500胺基磷酸树脂进行吸附，降低溶液中银离子浓度，分离出的载银树脂在超声波作用下分离出银粉，就可得到平均粒径为100nm的纳米银粉．实验结果表明，采用树脂吸附-化学还原的方法可以制备出粒度均匀的纳米银粉．     

固相反应法制备氢氧化镍和氧化镍超微粉

以草酸和镍盐为原料 ,在溶液中反应得到NiC2 O4 ·2H2 O ,进而在室温下与NaOH进行固相反应制得平均粒径为 1 0～ 2 0nm的超细粉体 β -Ni (OH) 2 。用NiCl2 ·6H2 O与NaOH在常温下进行固相反应 ,经 3 50℃处理分解可制备得到平均粒径为 2 0～ 3 0nm的NiO粉体。所需设备简单 ,操作方便易行。     

Influence of synthesis conditions on the preparation of nanosized ZrO<Subscript>2</Subscript> powders by evaporative decomposition of solutions

Nanosized ZrO2 powder was prepared by evaporative decomposition of solution（EDS）. The particle size is from 50 nm to 200 nm. This process has such advantages as high purity, precise compositional control, simple procedure and successive auto-operating. In this process, mixed solution of zirconium acetate and yttrium nitrate was atomized to from a fine mist and blown into the hot zone from the bottom of furnace. The solution was rapidly decomposed at 900℃ and the powder was collected by a filter system. The powder characteristics can be controlled by adjusting the concentration, droplet volume and decomposition temperature of the solution.