旋转喷吹反应自生铝基复合材料的工艺及显微结构

在大气条件下向铝和铝－镁合金液体内部旋转吹入氧气，氧与铝、镁反应，生成的Ａｌ２Ｏ３和ＭｇＡｌ２Ｏ４陶瓷颗粒分布在基体金属中。自生的Ａｌ２Ｏ３颗粒尺寸为０．１￣３μｍ，ＭｇＡｌ２Ｏ４颗粒尺寸为５￣１０μｍ。     

原位生长陶瓷相增强Al基复合材料的界面、微观结构及性能

本文对原位生长Ａｌ_４Ｃ_３与外加ＳｉＣ颗粒混杂增强Ａｌ（Ａｌ_４Ｃ_３·ＳｉＣ／Ａｌ）和原位生长Ａｌ_２Ｏ_３、ＴｉＢ_２颗粒混杂增强Ａｌ（Ａｌ_２Ｏ_３·ＴｉＢ_２／Ａｌ）两种复合材料的界面、微观结构和性能进行了研究。原位生长陶瓷相在基体中呈均匀分布。Ａｌ_２Ｏ_３和ＴＩＢ_２为尺寸１０ｎｍ～２μｍ的颗粒，Ａｌ_４Ｃ_３为长度０．２μｍ，直径０．０２μｍ的棒状单晶体。原位陶瓷相和Ａｌ基体之间的界面是清洁的，不存在中间过渡层。Ａｌ_４Ｃ_３和Ａｌ之间可存在的取向关系．Ａｌ_２Ｏ_３和ＴｉＢ_２粒子与Ａｌ之间不存在取向关系。两种复合材料都表现出优于ＳｉＣ_ｗ／Ａｌ复合材料的强度。     

TiO_2－Al－B系反应烧结制备的复相陶瓷和原位Al基复合材料

采用反应烧结方法，利用ＴｉＯ２，Ａｌ和Ｂ粉末间的放热反应在较低的温度下制备Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷和原位生长Ａｌ２Ｏ３和ＴｉＢ２弥散粒子增强Ａｌ复合材料Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷是密度ρ～０．８的多孔体，由尺寸约１０μｍ的生长单元构成晶粒，在陶瓷中还含有少量的Ａｌ３Ｔｉ．Ａｌ基复合材料中原位形成的Ａｌ２Ｏ３和ＴｉＢ２粒子尺寸小于２μｍ，在基体中呈现均匀分布，没有发现Ａｌ３Ｔｉ生成．这种原位Ａｌ基复合材料具有优于ＳｉＣｗ／Ａｌ复合材料的强度．     

Al_2O_3颗粒粒径和含量对α-Al_2O_3/Cu复合镀层性能的影响

本文研究了复合电沉积法制备的α－Ａｌ２Ｏ３／Ｃｕ复合材料的性能和磨损特征，测定了Ａｌ２Ｏ３粒径在０．５～５μｍ，含量在４～１６％时Ａｌ２Ｏ３／Ｃｕ复合镀层的硬度和磨损率，用扫描电镜对磨损形貌进行了分析，并对其磨损机制进行了探讨。结果表明，镀层中硬度随Ａｌ２Ｏ３含量增加呈线性增长，且含大颗粒Ａｌ２Ｏ３镀层的硬度略高于小颗粒镀层，Ａｌ２Ｏ３颗粒含量和粒径大小对磨损率和磨损机制有显著影响。     

以超微细Al2O3作种子乙酸乙烯酯的乳液聚合的研究

研究了以超微细Ａｌ２Ｏ３作种子的乙酸乙烯酯的乳液聚合以及所形成的复合材料的显微结构。聚合动力学研究结果表明，乙酸乙烯酯的聚合速率随Ａｌ２Ｏ３的用量的增加而下降；用量一定时，聚合速率则随Ａｌ２Ｏ３的粒径减小而降低。扫描电镜照片显示，Ａｌ２Ｏ３的粒径大于１ｕｍ时，Ａｌ２Ｏ３与聚乙酸乙烯酯的界面上有明显的微裂缝，而粒径为０．１ｕｍ时，Ａｌ２Ｏ３能均匀地分散在聚乙酸乙烯酯中且无裂缝存在。ＤＴＡ结果表明，超     

常压烧结ZTM／Al2O3复合陶瓷的力学性能

采用干法成型、常压烧结工艺制得致密的ＺＴＭ／Ａｌ２Ｏ３复合陶瓷材料。通过引入大颗粒的氧化铝，使ＺＴＭ陶瓷（氧化锆增韧莫来石陶瓷）的力学性能有明显提高。组成２０Ｖｏｌ．％Ａｌ２Ｏ３－２０Ｖｏｌ．％ＺｒＯ２－ｍｕｌｌｉｔｅ陶瓷材料，其断裂韧性为６．０６ＭＰａ·ｍ＾１／２，抗弯强度为４０３ＭＰａ。实验结果表明：Ａｌ２Ｏ３的弥散强化和ＺｒＯ２的相变增韧及微裂纹增韧是ＺＴＭ／Ａｌ２Ｏ３陶瓷的主要增韧机理。     

TiO2—Al—B系反应烧结制备的复相陶瓷和原位Al基复合材料

采用反应烧结方法，利用ＴｉＯ２，Ａｌ和Ｂ粉末间的放热反应的较低的温度下制备Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷和原位生长Ａｌ２Ｏ３和ＴｉＢ２弥散粒子增强Ａｌ复合，Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷是密度ρ－０．８的多孔体，由尺寸小于２μｍ，在基体中呈现均匀分布，没有发现Ａｌ３Ｔｉ生成，这种原位Ａｌ基复合材料具有优于ＳｉＣｗ／Ａｌ复合材料的强度。     

Pd/γ-Al2O3复合催化膜的热稳定性

由溶胶凝胶法制备出Ｐｄ/γ－Ａｌ２Ｏ３催化膜及镧掺杂改性的Ｌａ/Ｐｄ/γ－Ａｌ２Ｏ３膜,研究了镧的掺杂对Ｐｄ/γ－Ａｌ２Ｏ３膜热稳定性的影响．用ＤＴＡ、ＸＲＤ、ＢＥＴ分别对膜的晶相和微孔结构(包括比表面积、孔径和孔容)进行了研究,结果发现:镧的掺杂明显提高了α－Ａｌ２Ｏ３的相变温度和高温下Ｐｄ/γ－Ａｌ２Ｏ３催化膜的热稳定性．Ｐｄ/γ－Ａｌ２Ｏ３经１１００℃处理５ｈ后,其比表面积、孔径和孔容分别为４．４６ｍ２/ｇ、３５．１ｎｍ和０．０５１ｃｍ３/ｇ,而经镧掺杂改性的Ｌａ/Ｐｄ/γ－Ａｌ２Ｏ３膜的比表面积、孔径和孔容分别为５１．６ｍ２/ｇ、７．２ｎｍ和０．１３８ｃｍ３/ｇ．     

原位Al_2O_(3pl)/Ce-TZP复合材料的显微结构与力学性能

研究了原位生长Ａｌ２Ｏ３片晶／Ｃｅ－ＴＺＰ复合材料的显微结构与力学性能．结果表明,只要烧结温度适当,引入原位Ａｌ２Ｏ３片晶可同时提高复合材料的强度和断裂韧性．在所研究的范围内,以含 １５ ｖｏｌ％Ａｌ２Ｏ３的复合材料有最好的强韧化效果,而增韧效果又比增强效果明显．如果烧结温度过低或者Ａｌ２Ｏ３含量过高,则复合材料的力学性能反而下降．原位Ａｌ２Ｏ３片晶／Ｃｅ－ＴＺＰ复合材料的强韧化机理为应力诱导相交增韧和片晶增韧,两者起到协同增韧的作用．     

α—Al2O3晶体对氧化铝转相温度的影响

以工业氢氧化铝粉为原料,对其进行了添加α－Ａｌ２Ｏ３晶种的处理,研究了粉体添加晶种前后转相温度的变化情况。氢氧化铝原料粉在１２５０℃转变为α－Ａｌ２Ｏ３,而用湿磨工艺混入５ｗｔ％的α－Ａｌ２Ｏ３作为晶种后,在９００℃相转变开始发生,到１１００℃转相完成。粉体平均粒径０．３μｍ,优于原料粉的转相结果。     

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.