SiC纤维补强微晶玻璃基复合材料的界面结合

本文通过ＳｉＣ纤维对ＬＣＡＳ（Ｌｉ２Ｏ－ＣａＯ－Ａｌ２Ｏ３－ＳｉＯ２）和ＭＡＳ（ＭｇＯ－Ａｌ２Ｏ３－ＳｉＯ２）微晶玻璃的补强，观察和分析了在不同复合系统中纤维与基体的界面结合。在ＳｉＣ纤维／ＬＣＡＳ微晶玻璃复合系统中，发现纤维与基体之间有一中间界面层，它主要是在复合材料的烧结过程中通过扩散形成，并且于１２００℃时在界面上形成富Ｃ层。ＳｉＣ纤维／ＭＡＳ微晶玻璃基复合材料由于在烧结过程中有化学反应发生     

纤维涂层对复合材料力学性能的影响

对于ＳｉＣ纤维／ＭＡＳ微晶玻璃复合系统，发现在烧结温度下，纤维和基体之间有较严重的化学反应发生，界面结合强，力学性能较差．通过对ＮｉｃａｌｏｎＳｉＣ纤维加涂层，发现Ｎｂ２Ｏ５和ｃ涂层对复合材料的界面结合改善不大，而ＬＣＡＳ晶玻璃涂层能使纤维和基体间的界面结合明显减弱，力学性能大幅度提高，室温抗折强度和断裂韧性分别达３２７ＭＰａ和１３．９ＭＰａ·ｍ１／２．     

碳化硅和氧化铝陶瓷的热等静压氮化

通过对无压烧结、热压烧结和热等静压烧结ＳＩＣ陶瓷以及热压烧结的ＳｉＣ粒子补强Ａｌ２Ｏ３基复相陶瓷（ＳｉＣｐ－Ａｌ２Ｏ３）和ＳｉＣ粒子与ＳｉＣ晶须共同增强的Ａｌ２Ｏ３基复合材料（ＳｉＣｐ－ＳｉＣｗ－Ａｌ２Ｏ３）在氮气氛中进行高温氮化处理，成功地实现了这些材料的开口气孔表面裂纹的愈合。研究表明：热等静压氯化工艺可以显著提高ＳｉＣ和Ａｌ２Ｏ３陶瓷的抗弯强度，对断裂韧性也有较大的改善作用。对于热等静压烧结ＳｉＣ陶瓷，在１８５０℃和２００ＭＰａ氮气压力下氯化处理１小时后，其抗弯强度和断裂韧性分别由５８２ＭＰａ和５．７ＭＰａ·ｍ１／２提高到９０７ＭＰａ和８．４ＭＰａ·ｍ１／２；对于热压烧结的ＳｉＣｐ－Ａｌ２Ｏ３复相陶瓷和ＳｉＣｐ－ＳｉＣｗ－Ａｌ２Ｏ３复合材料，在１７００℃和１５０ＭＰａ氮气压力下氮化处理１小时后，其室温抗弯强度分别由４６０和７０５ＭＰａ提高到８９５和１０３３ＭＰａ。     

真空铸造高强度C/Mg复合材料

本文介绍用真空铸造法制造抗拉强度超过1000MPa的高强度C/Mg复合材料。将T300纤维经C-Si-O梯度涂层处理后单向排布于型腔内,在真空下注入ZM-5合金液,凝固后即得C/Mg复合材料零件或试样。试样的抗拉强度在纤维体积分数为0.35时达1050MPa。本文讨论C-Si-O梯度涂层对获得高强度复合材料的作用。     

(WC-Co/NiCrBSi)钎焊涂层结合机制及磨损性能研究

采用真空钎焊工艺,将ＷＣ－Ｃｏ硬质合金粉和ＮｉＣｒＢＳｉ（ＡＷＳＢＮｉ－２）合金粉钎焊到４５＃钢表面,得到（ＷＣ－Ｃｏ／ＮｉＣｒＢＳｉ）钎焊涂层。不同钎焊工艺下,涂层及涂层／基体的拉伸强度分别达１００—１４０ＭＰａ和３００－３６０ＭＰａ。初步分析了钎焊涂层结合机制。涂层的磨料磨损性能远高于同配比的火焰堆焊涂层及Ｃｏ－Ｃｒ－Ｗ堆焊层     

碳化硅渗透涂层粘胶碳纤维的制备

从粘胶纤维出发制成连续的ＳｉＣ涂层的碳纤维。在热解过程中进行聚碳硅烷溶液的ＰＳＩ处理。纤维经１０００℃高温烧成后得到Ｃ／ＳｉＣ纤维。因为碳与外表的ＳｉＣ同时在高温下生成，ＳｉＣ渗透到纤维内部，呈梯度结构。制备中使用了一种含多元胺的阻燃剂，这不仅使烧成时间大为缩短，而且使纤维的收率提高。Ｃ／ＳｉＣ纤维的收率为３５－３８％，拉伸强度为１．３－２．０ＧＰａ，弹性模量为７０－１３０ＧＰａ，纤维平均直径为４至６μ。本文还对纤维的热解动力学进行了研究，提出新的动力学模型，由此设计纤维的烧成程序。     

钎焊工艺对WC—Co／NiCrBSi复合涂层性能的影响

采用真空钎焊技术,在４５＾＃钢基体表面焊一层（ＷＣ－Ｃｏ／ＮｉＣｒＢＳｉ）复合涂层,研究了不同钎焊工艺对涂层自身结合强度、涂层与基体间连接强度以及涂层抗磨料磨损性能的影响。钎焊工艺为１０８０℃×１０ｍｉｎ时,涂层自身结合强度为１４６ＭＰａ;涂层与基体间的最高连接强度为３６７ＭＰａ。涂层的抗磨料磨损性能比Ｃｏ－Ｃｒ－Ｗ堆焊涂层和（ＷＣ－Ｃｏ／ＮｉｒＢＳｉ）火焰堆焊层的高。     

常压MOCVD制备MgO薄膜的研究

本文首次报道用常压金属有机化学气相沉积（ＡＰ－ＭＯＣＶＤ）在Ｓｉ（１００），ＳｉＯ２／Ｓｉ（１００）和Ｐｔ／Ｓｉ（１００）衬底上外延高质量的ＭｇＯ薄膜。研究了衬底温度与薄膜的取向性关系和ＭｇＯ薄膜的潮解特性。高纯ｍａｇｎｅｓｉｕｍａｃｅｔｙｌａｃｅｔｏｎａｔｅ［ｂｉｓ（２，４－ｐｅｎｔａｎｅｔａｎｅ－ｄｉｏｎｏ）ｍａｇｎｅｓｉｕｍ］［Ｍｇ（ＣＨ２ＣＯＣＨ２ＣＯＣＨ３）２］作为金属有机源，扫描电镜（ＳＥＭ），透射电镜（ＴＥＭ）和Ｘ－ＲＡＹ衍射实验显示，在较低的衬底温度（～４８０℃）下一次淀积成单晶膜。薄膜均匀，致密，结晶性和取向性很好，衬底温度（Ｔｓ）在４００℃到６８０℃之间，在Ｓｉ（１００）衬底上生长的ＭｇＯ薄膜都具有［１００］取向，在Ｓｉ（１００）、ＳｉＯ２／Ｓｉ（１００）和Ｐｔ／Ｓｉ（１００）衬底上生长的ＭｇＯ薄膜也都具有［１００］取向。     

炭／炭复合材料在1500℃的抗氧化

本文研究了Ｃ／Ｃ复合材料ＭｏＳｉ２涂层系统的抗氧化性能。结果表明，ＭｏＳｉ＿２涂层系统具有１５００℃长时间抗氧化和优良的抗热震性能，在１５００℃时，２４２ｈ的氧化失重仅为０．７５％；长时间的氧化失重速率稳定在２．４３×１０－５ｇ／ｍ２·ｓ的极低水平。     

SiC纤维／LCMAS微晶玻璃基复合材料的界面结合和力学性能

本工作通过在母体玻璃中引入ＭｇＯ后进行热处理得到一系列具有不同热膨胀系数的微晶玻璃．ＳｉＣ纤维／ＬＣＭＡＳ微晶玻璃基复合材料在烧结条件下，在纤维和基体间形成一厚度约为２μｍ的界面层．纤维、基体间的界面剪切应力通过单根纤维压出法测试，发现纤维、基体间的界面剪切强度对复合材料的力学性能有严重的影响，并且ＳｉＣ纤维／ＬＣＭＡＳ系微晶玻璃基复合材料具有较高的界面剪切强度，通过降低基体的热膨胀系数减弱界面剪切强度，可使复合材料的强度和断裂韧性都得到明显的改善．     

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.