改性溶胶-凝胶法制备ZrO_2纳米晶粉及其团聚控制

对溶胶 -凝胶法进行改性 ,使凝胶聚沉为沉淀物 ,进而可以成功地合成ZrO2(9%Y2O3)纳米粉体。采用热重 -差热(TG -DTA)分析、粒度分布分析、透射电子显微镜(TEM)和X射线衍射(XRD)测试法对粉料制备工艺过程进行了研究。结果表明 ,改性的溶胶 -凝胶法在聚沉前加入分子量大小不同的表面活性剂 ,聚沉后采用无水乙醇超声分散 ,可以有效地消除团聚现象。沉淀产物在450℃以下可以完全分解为ZrO2(Y2O3)粉体 ,600℃煅烧颗粒晶粒度为14nm。     

纳米ZrO2——一种很有前途的远红外辐射材料

对纳米ZrO2颗粒的制备、改性、表征及其作为远红外辐射材料的应用作了介绍。对于纳米ZrO2颗粒的制备，重点介绍了化学沉淀法、溶胶-凝胶法以及微乳液法工艺，此外，简介了超声化学法、高温喷雾分解法、冷冻法等工艺；纳米ZrO2颗粒的改性，着重介绍了提高其远红外发射性能的手段；并介绍了其远红外发射性能、物相分析(XRD和UV Raman)和热分解(IES)等表征测试手段。     

纳米ZrO2--一种很有前途的远红外辐射材料

对纳米ZrO2颗粒的制备、改性、表征及其作为远红外辐射材料的应用作了介绍.对于纳米ZrO2颗粒的制备,重点介绍了化学沉淀法、溶胶-凝胶法以及微乳液法工艺,此外,简介了超声化学法、高温喷雾分解法、冷冻法等工艺;纳米ZrO2颗粒的改性,着重介绍了提高其远红外发射性能的手段;并介绍了其远红外发射性能、物相分析(XRD和UV Raman)和热分解(IES)等表征测试手段.     

无定形纳米ZrO2表面改性研究

采用溶胶-凝胶法制得粒径为57nm的无定形纳米ZrO2粒子.用硅烷偶联剂KH560、KH570、A151、钛酸酯、硬脂酸等表面活性剂对其表面进行修饰.修饰后对改性效果进行激光粒度,红外光谱,扫描电镜,透射电镜,X射线衍射分析.实验证明:A151改性效果较好,改性后无机纳米粒子表面的羟基和有机集团发生化学键结合,无机纳米粒子表面性质由亲水憎油向亲油憎水转变.     

非水解溶胶-凝胶法制备氧化钇稳定氧化锆粉体

非水解溶胶-凝胶法(Non-hydrolytic sol-gel,NHSG)作为一种新的合成方法,融合了溶胶-凝胶法和溶剂热两者的优势。本文分别采用回流和容弹两种NHSG工艺制备了纯ZrO2和氧化钇稳定的氧化锆(YSZ)粉体。DTA和XRD分析结果表明:容弹工艺制备的纯ZrO2和YSZ粉体在凝胶阶段就已具有较高的结晶度,且YSZ粉体经330℃热处理后具有较完整的四方晶相结构;回流工艺制备的产物在凝胶阶段其无定形程度较高,经500℃左右热处理析出晶体。两种NHSG工艺制备粉体中单个颗粒尺寸绝大部分都在100nm以下。     

静电层层自组装法制备纳米ZrO2/活性炭复合材料及其吸附性能研究

采用静电层层自组装技术和溶胶-凝胶法将不同层数、不同含量的纳米二氧化锆(ZrO2)粒子组装于活性炭表面,得到一种新型的复合材料。用比表面测定(N2-BET)、X射线荧光光谱(EDXRF)等对其进行了表征。系统地研究了纳米ZrO2改性的活性炭对水中2,4-二硝基酚的吸附性能。结果表明,改性后活性炭对2,4-二硝基酚的吸附符合Freundlich模型,吸附过程主要受分配作用控制,吸附容量比改性前提高了25%,而接触时间和初始浓度对吸附效果具有显著影响,并且酸性条件有利于吸附的进行。     

不同粒径单分散SiO2粒子的制备与表面改性

以正硅酸乙酯为原料,采用溶胶-凝胶法及种子生长法制备出不同粒径(290nm、960nm、1.3μm和1.9μm)的SiO2胶体颗粒,并研究了KH570对SiO2胶体颗粒表面疏水性的影响。粒度分析、扫描电镜及X射线衍射分析结果表明,产物均为球形单分散SiO2胶体颗粒;而接触角、表面羟基数和亲油化度等测试结果显示,KH570浓度和改性时间对SiO2胶体表面性质影响显著,且丙酮作为助剂改性效果比水更好,最佳条件是以丙酮为助剂,使用1%KH570回流处理6h。此外,在存在KH570时进行溶胶-凝胶过程可一步制备出直径为1.9μm的单分散SiO2疏水颗粒。     

花生壳纳米纤维素超疏水气凝胶的制备及在棉织物上的应用

以花生壳粉为原料,通过化学机械法从中提取纳米纤维素,采用溶胶-凝胶法,在花生壳纳米纤维素悬浮液中加入甲基三甲氧基硅烷以对其进行改性,并采用冷冻干燥法最终制备了纳米纤维素超疏水气凝胶.将通过喷涂的方法使纳米纤维素超疏水气凝胶和聚二甲基硅氧烷(PDMS)整理到棉织物上,分别对超疏水气凝胶和超疏水棉织物进行分析和表征.结果表...     

铜型无机抗菌材料的改性研究

研究了添加电解质、表面活性剂和有机溶剂对铜型抗菌白炭黑性能的影响.采用溶胶-凝胶法制备出白炭黑载体,选用Cu2+作为抗菌离子,亚硝酸钠(电解质)、十二烷基苯磺酸钠(表面活性剂)和乙醇(有机溶剂)作为添加剂.运用ICP、粒度分布仪等对改性后的抗菌白炭黑进行表征,采用菌落计数法(菌种选用大肠杆菌)对改性后样品的抗菌性能进行研究.结果表明:通过改性,铜型抗菌白炭黑的抗菌离子含量和杀菌率均有所提高；粒径均一,粒度分布窄；热稳定性较好.     

碳热还原协同溶胶-凝胶法合成纳米ZrB2粉末

利用ZrO2-B2O3-C反应体系碳热还原的基本原理,分别使用正丙醇锆(Zr(OC3H7)4)、硼酸(H3BO3)和蔗糖(C12H22O11)为原料,采用溶胶-凝胶-碳热还原法合成了二硼化锆(ZrB2)纳米粉末。我们首先使用络合剂醋酸(AcOH)修饰Zr(OC3H7)4,以防止Zr(OC3H7)4的快速水解;其次,选用蔗糖作为碳源,是考虑到蔗糖热解时可以完全分解为碳,这样可以准确计算热解过程碳的生成量。此外,研究了凝胶温度对ZrB2纳米粉末形貌的影响。结果表明:当起始原料B/Zr(mol.)=2.3、热解温度为1 550℃时,通过碳热还原协同溶胶-凝胶法成功合成了单相ZrB2纳米粉末;当凝胶温度分别为65、75和85℃时,ZrB2纳米粉末形貌从球状演变为链状,最后生长为棒状,生长机理为定向吸附。     

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.