Preparation of silver tin oxide powders by hydrothermal reduction and crystallization

Silver tin oxide composite powders were synthesized by the hydrothermal method with a silver ammine solution and a Na2SnO3 solution as raw materials. H2C2O4 was used as the co-precipitator of silver ions and tin ions. The co-precipitation conditions were investigated. The results show that the co-precipitate of Ag2C2O4 and Sn（OH）4 is available when the pH value of the solution is 4.27-8.36. Using the obtained precipitate as precursor,the reduction of Ag＋ and the crystallization of tin oxide were carried out simultaneously by the hydrothermal method and silver tin oxide composite powders were obtained. The composite powders were characterized by X-ray diffraction （XRD） analysis,scanning electron microscope （SEM）,and energy spectrum analysis. The results show that the silver tin oxide composite powders are small with a diameter of about 2 μm and with homogeneous distribution of tin.     

Influences of dehydrating process on properties of ATO nano-powders

1　INTRODUCTIONCrystallineSbdopedtinoxide (ATO) ,cassiteritestructure ,isawidebandgapn typesemiconductor.Be causeofitsopticalproperty (transparentforvisiblelightandreflectiveforIR )andelectroconductibility ,goodchemicalandmechanicalstability ,ithasmanyapplica tions,suchastransparentconductiveelectrodes ,photo voltaicdevices ,photosensors ,catalyst,antistaticcoatingsandelectrochromicmaterials[14 ] .AvarietyoftechniqueshavebeenusedtoprepareATOsuperfinepowders ,someinvolvedryprocesses ,ot…     

Preparation and electrochemical properties of nanosized tin dioxide electrode material by sol-gel process

1　INTRODUCTIONTinoxideisawideenergy gapsemiconductorandhasfoundmanytechnologicalapplicationssuchascatalystsforoxidationoforganics,solid stategassen sorsandopticalelectronicdevices[1,2 ] .Recently ,sev eraltin oxide basedcompoundswerereportedtobegoodcandidatesasanodesforlithiumionbatteriesin steadofcarbonaceouselectrodes[36 ] ,theelectro chemicalreactionoccurringinthesecompoundsisnottheintercalationoflithiumintoahoststructure .Forbulksamplesofamorphousandcrystallinetinoxide ,adecomposition…     

Indium tin oxide nanosized composite powder prepared using waste ITO target

Indium tin oxide （ITO） nano-particles were prepared directly using waste ITO target, which had been coated by magnetron controlled sputtering. The waste ITO target was cleaned with de-ionized water, and then dissolved in acid, filtrated, neutralized, manipulated through azeotropic distillation and finally dried, and in this way the precursor of indium tin hydroxide was obtained. The nanosized rio composite powder was prepared after the precursor heat-treated at 500℃ for 2 h. TEM images show a narrow distribution of particle size is 5-20 nm and the particle size can be controlled. Its granule has a spherical shape and the dispersion of the particle is well. X-ray diffraction （XRD） patterns indicate the only cubic In2O3 phase in the ITO powder hot-treated at 500℃. The purity of ITO composite powder is 99.9907%. The content of radium within filtrate was detected by using the EDTA titration of determination of indium in the ITO powder and ITO target. Appropriate amount of SnCl4.5H2O was dissolved in the filtrate, and then ITO powder containing 10 wt.% SnO2 was successfully prepared by heat-treating.     

柠檬酸盐凝胶法制备纳米晶SnO2的络合过程及其相结构研究

以SnCl2和柠檬酸为前驱物，无水乙醇为溶剂制备了纳米级SnO2。采用红外光谱（FTr—IR）、XRD和TEM测试技术研究了产物的络合过程和组织结构。结果表明，制备过程中形成了柠檬酸锡，其结构特征主要为双齿配位，部分为桥式配位，热处理后的粉体为10nm左右的分散性良好、尺寸分布均匀、具有优良热稳定性的金红石SnO2，形貌为等轴晶。     

不同体系水热制备银氧化锡复合粉体的研究

分别采用氨水和柠檬酸作为溶液中银离子的配体,草酸、亚硫酸钠和柠檬酸作为还原剂,水热制备Ag-SnO2复合粉体。对Ag-SnO2复合粉体进行了差热分析、X射线衍射、扫描电镜和元素面扫描分析。结果表明:不同体系均可水热制备银氧化锡复合粉体。在以氨水为配体,分别以亚硫酸钠和草酸为还原剂的体系中,银和二氧化锡沉积完全。以亚硫酸钠为还原剂的体系中所得复合粉体为片状结构,厚度约为300nm,而以草酸为还原剂所得复合粉体为球形结构,粒径约为100nm。以柠檬酸为配合剂和还原剂的水热体系中二氧化锡沉积不完全,所得复合粉体为不规则球形,粒径较小,约为30nm。     

Preparation of tetragonal CaO-ZrO_2 nano-powder by chemical coprecipitation method

1　INTRODUCTIONNanometerZrO2 ,whichisanimportantrawmaterialtoprepareZrO2 ceramic ,canbealsousedasrawmaterialoffire resistant ,wearableanderosion resistantproducts .ZrO2 ceramicistraditionallyusedasfire resistantmaterials ,coating ,ceramicglazeandfoundry .However ,withthedevelopmentofelec tronicandnewmaterialindustry ,itsapplicationex pandstothefieldsofartificialteethandartificialim plantingbonesduetoits goodchemicalstability ,wearability ,physiologicallyerosion resistantpropertyandbiolog…     

Production of nanoscale Ba(Zn1/3Nb2/3)O3 microwave dielectric ceramics by polymerised complex method

Ba(Zn_1/3Nb_2/3)O₃ nanoparticles have been synthesized by a polymerised complex method by using precursor materials of barium nitrate, zinc acetate, niobium oxide, hydrofluoric acid and citric acid. Thermal decomposition characteristics and crystallization behavior of the powders were investigated by the thermogravimetric and differential thermal analysis, X-ray diffractometer and Fourier transform infrared spectroscopy. Ba(Zn_1/3Nb_2/3)O₃ phase started to form at low temperature of 400 °C and, single phase Ba(Zn_1/3Nb_2/3)O₃ perovskite structure was obtained at 1000 °C. Microstructural investigation revealed that the major particle size of Ba(Zn_1/3Nb_2/3)O₃ nanoparticles were in the range of 80–110 nm with spherical morphology and homogeneous size distribution. But the powders also contained some agglomeration.     

氧化钨的形貌结构对纳米WC粉末均匀性的影响

研究了在传统氢还原工艺制备纳米碳化钨粉末过程中不同氧化钨的形貌结构对纳米W/WC粉末均匀性的影响,并对粉末及其WC-Co烧结体的性能进行了表征。结果表明,用具有疏松、多孔形貌结构的细小氧化钨颗粒更容易制备出结构较疏松、分散性较好的纳米W粉和WC粉。晶粒聚集和异常粗大颗粒的产生,主要与碳化过程中团聚纳米钨粉颗粒因烧结合并增粗有关。     

DEPENDENCE OF SINTERABILITY ON STATE OF AGGLOMERATION OF ULTRAFINE ZrO_2，（Y_2O_3） POWDERS

ＤＥＲＳＤＥＰＥＮＤＥＮＣＥＯＦＳＩＮＴＥＲＡＢＩＬＩＴＹＯＮＳＴＡＴＥＯＦＡＧＧＬＯＭＥＲＡＴＩＯＮＯＦＵＬＴＲＡＦＩＮＥＺｒＯ_２，（Ｙ_２Ｏ_３）ＰＯＷＤＥＲＳ￥Ｇｅ，Ｒｏｎｇｄｅ；Ｌｉｕ，Ｚｈｉｈｏｎｇ；Ｃｈｅｎ，Ｈｕｉｇｕａｎｇ；Ｚｈａｎｇ，...     

Preparation of flake AgSnO2 composite powders by hydrothermal method

Silver-tin oxide composite powders and silver powders were synthesized by hydrothermal method using NHs to complex Ag^＋, SO3^2- to reduce Ag（NH3）2^＋ and Na2SnO3 as the source of tin. The powders were characterized by XRD, SEM and EDX. The results show that there are macroscopic and microscopic differences between two kinds of powders. Spherical silver powders are 3μm in diameter, and silver-tin oxide composite powders are mainly flake of about 0.3μm in thickness. Silver crystal in silver-tin oxide composite powders is preferentially oriented in the （111） crystallographic direction and its oriented index is 2.581. Crystal lattice parameter of silver crystal of silver tin-oxide composite powders is 0.409 34 nm, larger than 0.408 68 nm of silver powders. The XPS analysis shows that silver in silver-tin oxide composite powders is metallic silver and tin oxide in silver tin-oxide composite powders has the red shift for Sn^4＋（3d（5/2）） and O^2-（1s）.     

Preparation of antimony-doped nanoparticles by hydrothermal method

Antimony-doped tin oxide (ATO) nanoparticles were prepared by the mild hydrothermal method at 200℃ using sodium stannate, antimony oxide, sodium hydroxide and sulfuric acid as the starting materials. The doped powders were examined by differential thermal analysis(DTA), X-ray diffractometry(XRD) and transmission electron microscopy(TEM). The doping levels of antimony were determined by volumetric method and iodimetry.The results show that antimony is incorporated into the crystal lattice of tin oxide and the doping levels of antimony in the resulting powders are 2.4%, 4.3%and 5.1%(molar fraction). The mean particle size of ATO nanoparticles is in the range of 25 - 30 nm. The effects of antimony doping level on the crystalline size and crystallinity were also discussed.     

A Comparative Study on the Microstructure and Properties of ITO Targets and Thin Films Prepared from Two Different Powders

With the rapid development of indium tin oxide(ITO) in the electronic display industry, choosing which raw powders to prepare high-quality ITO targets has always been a controversial topic. In the work, in order to clearly understand the effect of the raw powders on the microstructure and properties of ITO targets and thin films, tin-doped indium oxide(dITO) and In_2O_3-SnO_2 mixed(mITO) powders were chosen to prepare ITO targets for depositing the films and a comparative study on their microstructure and properties was conducted. It is found that,(1) dITO targets possess a higher solid solubility of tin in indium oxide and more uniform elemental distribution, while there are a higher density, a finer grain size and a higher mass ratio of In_2 O_3 to SnO_2 for the mITO targets;(2) dITO films with more coarser columnar grains and a rougher surface prefer to grow along the [100] direction in an Ar atmosphere;(3) the conductive property of ITO films only depends on the doping amount of tin and is independent of the raw powders and the preparation process of the target source;(4) dITO films possess the superior optical property and narrower optical band gap;(5) the etching property of mITO films is superior to that of dITO films due to the lower solid solubility of tin in indium oxide.     

Preparation of ZrO2 spherical nanometer powders by emulsion processing route

ZrO2 precursor powders containing 3% Y2O3 were prepared via a single emulsion processing route and a double emulsion processing route. In both routes xylol was used as the oil phase, span-80 as the surfactant, and an aqueous solution containing zirconium or ammonia as the water phase. The calcination of the precursor powders was performed at 600 ℃ for 2 h, leading to tetragonal phase ZrO2 nanometer powders. The ZrO2 powders and the precursor powders were analyzed and characterized by means of TGA-DTA, XRD, TEM, BET and laser particle size analyser. The results indicate that xylol-span-80-water phase system contain more water phase, which to a certain extent overcomes the disadvantages of low output by emulsion route in preparing powders. The best volume ratio Vxylol ： Vspan-80 ： Vwater= 95 ： 5 ： 25 leads to the attaining of powders. The special tetragonal phase powders with less agglomeration were prepared via either the single emulsion processing route or the double emulsion processing route according with the ratio. But compared to the single emulsion processing route, the powders prepared via the double emulsion processing route display smaller particles with more even size distribution, the average size of around 15 nm.     

纳米钨/碳化钨粉末的形貌遗传特性及其对粉末均匀性的影响

为研究氧化钨的形貌结构对纳米钨粉末制品均匀性的影响,用X射线衍射分析仪和电子扫描电镜对普通黄钨在660℃下还原的过程产物进行了分析、观测。同时分别以普通黄钨和强力球磨分级处理的细黄钨为原料,采用经优化的工艺条件制备出了纳米W、WC粉末,并对粉末及其快速烧结体的显微组织结构进行了观察、分析。结果表明,不同形貌结构原料制备的纳米W、WC粉末,均呈现出不同程度的形貌结构遗传特性,强力球磨分级处理所获细黄钨颗粒细小、形貌结构疏松,更容易制备出结构较疏松,分散性较好的纳米W、WC粉末。     

Novel method for preparation of silver-tin oxide electrical contacts

A novel method of coating tin oxide particles with silver by an electroless plating process has been developed to produce silver-tin oxide electrical contact materials. A powder metallurgy process has been developed to consolidate the electroless plated silver- tin oxide composite powders. The effect of the various plating conditions on the morphology of the composite powder was studied using the transmission electron microscope (TEM) and the scanning electron microscope (SEM). An optical microscope and electron microprobe analysis (EMPA) were used to characterize the structure of the sintered silver-tin oxide compact. Ductility and hardness were measured to ensure that the mechanical properties are adequate, and electrical conductivity was also measured.     

Preparation of pure SnO_2 powders from tin slag of printed circuit boards waste

The recycling method and principle of SnO2 from the tin slag of printed circuit boards(PCB) waste were investigated. In this study, pure SnO2 powders were obtained through a multi-step process including ball-milling, roasting, dissolving, precipitating, and pickling. The total recovery rate of tin can be up to 91 %. The SnO2 powders obtained is the single phase, and the content of SnO2 is up to 99.9 %. However, the SnO2 particles are easier to agglomerate during the precipitation process. The agglomerate SnO2 particles are about 7.778 lm in mean particle size(D50). This preparation method presents a viable alternative for the tin slag recycling. The tin is not only recycled, but also reused directly to prepare pure SnO2 powders.     

低热固相法合成镁铝尖晶石

以分析纯碱式乙酸铝、硝酸镁为原料,柠檬酸为配合剂,采用低热固相反应制备前驱体,然后通过煅烧的方式获得了MgAl_2O_4粉体.研究了煅烧温度、柠檬酸用量对MgAl_2O_4粉体性能的影响.结果表明,可在全固相条件下通过低热固相反应得到Mg和Al分子级混合的前驱体,该前驱体煅烧到700 ℃保温3 h形成含有部分阳离子缺陷的尖晶石晶相,随温度升高,逐渐转化为结晶完整的尖晶石.柠檬酸使用量符合化学计量比n(C_6H_8O_7):n(Mg+Al)为1:1时能够获得比表面积达到166 m~2/g的MgAl_2O_4粉体.     

Comparing Microstructures of ITO Sputtering Targets Prepared by Tin Doped Indium Oxide Powders and In2O3- SnO2 Mixed Powders

磁控溅射ITO靶材制备ITO透明导电薄膜作为平板显示、太阳能电池、气敏元件等电子器件的电极材料,需要ITO靶材具有高纯度、高均匀性、高密度、高导电性的特点。对比研究了ITO共沉淀粉与In2O3、SnO2单体混合粉同炉烧结ITO靶材的微观组织结构差异,如：晶粒尺寸分布、晶粒形貌、元素分布、烧结速率等。结果表明：单体混合粉的烧结速率要比共沉淀粉的烧结速率高,但是前者烧结ITO靶材的微观组织结构不及后者烧结的均匀性好。对比而言,共沉淀粉更容易获得结构组织均匀的ITO靶材,但前提是要合理的设计烧结工艺抑制烧结过程中In2O3的分解。研究结果将会对提高ITO靶材微观组织均匀性和减少靶材毒化,进而提高靶材生产效率提供有益的参考     

Characterization of nanometer tungsten powders

Three types of tungsten powders were prepared by hydrogen reduction of three precursor powders at low temperature,which were used as samples,and were then characterized by Brunauer-Emmer-Teller (BET) method,scanning electron microscopy (SEM),transmission electronic microscopy (TEM),small angle X-ray scattering (SAXS),and field-emission scanning electron microscopy (FESEM) respectively.The results showed that although BET and SEM could not characterize the particle size of nanometer powders,they were important means of assistance to exclude non-nanometer powders.TEM and FESEM could directly measure the particle size of nanometer powders,but this needs a lot of time,to count the average particle size and particle size distribution.SAXS could not describe the state of agglomeration.By the combination of FESEM and SAXS,the particle size,particle size distribution,and particle shape of nanorneter powders could be preciscly characterized.