制备工艺对纳米级铟锡氧化物(ITO)形貌和电性能的影响

以SnCl4·5H2O、In和浓盐酸为原料,采用化学共沉淀法制备出了纳米级锡掺杂氧化铟(ITO)导电微粉,系统地研究了掺杂量,共沉淀温度,pH值,热处理时间、温度对粉体粒度、形貌和电性能的影响规律。研究表明,合成的ITO粉体分散性较好、导电性能优异,粒径在40nm左右具有立方铁锰矿结构。在ITO纳米导电粉的制备过程中,共沉淀温度和滴定终点pH值对其形貌和性能有很大影响,当共沉淀温度在60℃左右,pH=6时制得的粉体性能最佳。煅烧条件对粉体的形貌、粒度和导电性也有较大的影响,在700℃,4h条件下可以制得导电性能良好,结晶完好,粒度分布均匀的ITO粉体。掺入Sn(Ⅳ)的量对载流子的迁移率有很大的影响,在掺杂浓度为10%左右可制得导电性极佳的纳米ITO粉体。     

乙二醇溶剂热合成自组装SrTiO3片状纳米结构及其光催化性能

以钛酸四正丁酯((C4H9O)4Ti)水解沉淀的钛羟基氧化物和硝酸锶(Sr(NO3)2)为反应原料,以氢氧化钾(KOH)为矿化剂,以乙二醇((HOCH2)2)为溶剂,经200℃溶剂热反应得到了由纳米颗粒自组装形成的SrTiO3片状纳米结构。分别用XRD、SEM、TEM表征SrTiO3粉体的物相结构和微观形貌。通过光催化降解罗丹明B(RhB)对比研究了乙二醇溶剂热合成的纳米颗粒自组装SrTiO3片状纳米结构和水热合成的SrTiO3粉体的光催化性能,结果表明,乙二醇溶剂热合成的SrTiO3自组装片状纳米结构具有更加优异的光催化性能。     

双氮二甲基甲酰胺介导溶剂热合成CuS粉体及表征

以CuCl2.2H2O为铜源,N,N-二甲基甲酰胺(N,N-dimethylformamide,DMF)为溶剂,分别以L-半胱氨酸、硫脲、硫代乙酰胺为硫源采用溶剂热法在130℃下反应8h得到了不同形貌的硫化铜(CuS)纳米粉体。用X射线粉末衍射仪、X射线光电子能谱、场发射扫描电子显微镜、透射电子显微镜、紫外可见吸收光谱手段对粉体的结构、形貌、成分及光学性能进行表征。研究表明,硫源对产物的结构和形貌有较大的影响。采用L-半胱氨酸为硫源得到的产物多呈纳米颗粒无序堆积的无定形态,而采用硫脲和硫代乙酰胺为硫源得到的是纳米棒组成的球状粉体。讨论了不同硫源对CuS粉体的形成及其形貌的影响,并对各种形貌CuS粉体的形成机理进行了简单的探讨。     

溶剂热辅助溶胶-凝胶法制备微纳米晶ZrSiO4陶瓷

采用溶剂热辅助溶胶-凝胶法,以氯氧化锆(ZrOCl_2·8H_2O)和正硅酸乙酯(TEOS)为原料,以乙醇溶液为溶剂介质,制备锆石(ZrSiO_4)前驱体,将前驱体在1 400℃下煅烧6 h,即得微纳米晶ZrSiO_4陶瓷(200～450 nm)。借助X射线衍射仪、扫描电子显微镜和密度测试仪对固化体进行分析测试,研究溶剂热温度和乙醇浓度对固化体的物相结构、微观形貌及致密性的影响规律。研究发现,溶剂热温度和乙醇浓度对固化体的合成及致密性具有较大的影响。在溶剂热温度为110℃及乙醇浓度为60%条件下,获得的微纳米晶ZrSiO_4陶瓷具有较高密度(4.46 g/cm~3)。     

苹果酸络合物沉淀法制备纳米二氧化钛粉体

提出了一种苹果酸络合物沉淀法制备高纯纳米二氧化钛粉体方法。使含有适量表面活性剂的Ti4+与C4H4O52-反应生成苹果酸钛络合物前驱体Ti2O2(OH)2C4H4O5·4H2O,经洗涤、干燥,在900℃下煅烧2h,得到纳米TiO2粉体。经XRD和TEM检测,产物纳米二氧化钛为金红石型结构,平均粒径为40nm。     

共沉淀法制备Nd3+:Y2O3透明陶瓷

以Y2O3为基质材料,掺杂不同含量的Nd3+添加PEG和(NH4)2SO4为分散剂,采用共沉淀法制备出性能良好的Nd3+:Y2O3纳米粉.对前驱体和不同温度下煅烧后的粉体进行差热热重、X射线衍射、比表面积和透射电镜等分析.结果表明,前驱体产物为Y2(OH)5(NO3)·nH2O时,Nd3+完全固溶于Y2O3的立方晶格中,Nd3+:Y2O3粉体大小均匀,近似球形.随着煅烧温度的升高,颗粒逐渐长大,900℃煅烧2h后颗粒尺寸约为40～60nm;粉体在1700℃和真空度为1×10-3Pa条件下烧结6h得到的Nd3+:Y2O3透明陶瓷的透光率接近78%.     

溶胶-凝胶法制备纳米Y2O3粉体

为了改善Y2O3粉体的分散性,提高其烧结活性,试验以三乙醇胺和氨水为凝胶剂,利用溶胶-凝胶方法合成了纳米级Y2O3粉体,采用差热/热重、X射线衍射、透射电镜研究了前驱体的组成、前驱体在不同的煅烧温度下的物相变化以及煅烧粉体的分散性.结果表明,前驱体的组成为Y2(OH)5.14(NO3)0.86H2O,在500℃保温2h可直接生成立方相的Y2O3,煅烧至1000℃保温2h得到了结晶度高、分散性好、平均粒径为50nm、近球形的YO纳米粉体;三乙醇胺的加入有利于提高YO粉体的分散性.     

耐高温Al2O3/TiO2纳米复合粉体的制备及表征

以TiCl4、Al2(SO4)3为原料,采用液相沉淀法制备了Al2O3/TiO2纳米复合粉体,同时对该纳米复合粉体的相变过程和晶粒生长过程进行了详细的研究,对紫外-可见光吸收进行了检测.结果表明:纳米TiO2粉体经Al2O3复合后,其耐温性能得到极大提高,复合粉体经950℃煅烧后锐钛矿相含量仍然在77%,晶体粒径在20nm左右;锐钛矿向金红石晶型的转变温度在950～1100℃的高温区.复合粉体在低温煅烧后,紫外-可见吸收强度较纯纳米TiO2有较大提高,高温煅烧后,复合晶的紫外光吸收红移.     

单分散纳米氧化铟锡粉末的水热合成

以金属铟和锡为原料,于碱性环境240℃水热合成12h并经500℃煅烧2h得到了 粒径为70±10nm,比表面积为11 m²／g的高纯氧化铟锡(ITO)粉末.由SEM、激光粒度测试 仪和BET三种方法分析得到的粉末平均粒径相吻合,证明制备的粉末是单分散状态的.研究 还发现,提高铟锡初始浓度和氢氧化钠过量浓度均有利于小粒径单分散ITO粉末的制备,但 过高的氢氧化钠过量浓度会使粉末出现团聚.     

纳米TiO_2复合抗菌材料的制备及其性能研究

采用溶胶-凝胶技术,以钛酸正丁酯为前驱体,于450~700℃的空气气氛中煅烧3h,分别制得了有、无SiO2包膜的掺杂银、镍金属离子的复合纳米TiO2抗茵粉体.采用TG-DSC、XRD、SEM等方法对产物进行表征,并选用大肠杆茵、枯草芽孢杆茵为受试菌种,采用抑茵圈实验对粉体抗茵性进行检测.结果表明,在该实验条件下制备的纳米TiO2>为锐钛矿型,通过包覆SiO2能有效地减小SiO2的粒度,防止团聚的产生,粉体抗茵性能良好,无SiO2包膜的抗茵粉体抑茵效果优于有包膜的抗茵粉体,在700℃下煅烧的抗茵粉体抑茵效果最好.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.