上浆剂对碳纤维增强双马树脂基复合材料力学性能的影响

通过对包覆不同上浆剂的碳纤维增强双马树脂基复合材料在不同温度下的层间剪切强度、弯曲性能和三点弯曲试样破坏模式进行研究,探讨了上浆剂对碳纤维增强双马树脂基复合材料力学性能的影响。研究表明不同的国产上浆剂对CCF300/QY8911复合材料在高温环境时的层间剪切强度和弯曲强度有影响;室温下不同上浆剂的CCF300/QY8911复合材料的力学性能与T300/QY8911复合材料的相当,而高温下其力学性能的保持率低于T300/QY8911复合材料的。     

上浆剂对国产碳纤维复合材料界面性能的影响

为了研究两种不同上浆剂和湿热环境对国产300级碳纤维/环氧树脂体系微观界面性能的影响,采用单丝断裂法,测试分析了去浆前后碳纤维单丝复合体系在自然干态、湿热处理3 d及湿热处理6 d的状态下微观界面剪切应力的变化.结合对扫描电镜(SEM)、原子力显微镜(AFM)及X射线光电子能谱(XPS)等测试结果的分析,研究了碳纤维上浆剂对微观界面性能及其界面耐湿热性能的影响.结果表明:去浆前后A300碳纤维表面均有明显沟槽;上浆剂1并未使A300碳纤维表面粗糙度有明显变化,但上浆剂2使A300碳纤维表面粗糙度减小,而两种上浆剂均使A300碳纤维表面含氧极性官能团含量减少.两种上浆剂对制备的复合材料界面性能和耐湿热性能都有较大的提高,其中上浆剂1在自然干态下对界面性能的提高更明显.     

国产ZT7H碳纤维表面状态及其复合材料界面性能

目前我国在高性能碳纤维研发生产方面已取得了突破性的进展。本文选用不同批次和牌号的国产ZT7H碳纤维,对其进行去浆和上浆处理,并制备碳纤维增强环氧树脂基复合材料,探究国产H1型上浆剂对ZT7H碳纤维表面形貌和微观界面性能的影响及不同牌号碳纤维复合材料界面性能的差异。研究表明,H1上浆剂增加了碳纤维表面粗糙度和极性组分含量,增强了湿热老化前后复合材料的微观界面力学性能。同时,碳纤维织物的编织方式对其复合材料的静态力学性能和界面性能有很大影响。实验证明,国产ZT7H碳纤维的性能已超过东丽T700碳纤维,但其加工工艺性仍有待提升。      

国产T800碳纤维用氰酸酯树脂开发及其复合材料性能

基于飞行器减重对耐高温结构复合材料的应用背景,为了拓展国产T800碳纤维增强氰酸酯复合材料体系的应用,通过对国产T800碳纤维表面上浆剂的分析,开展适于国产T800碳纤维的氰酸酯树脂基体配方设计,研究国产T800碳纤维/氰酸酯复合材料的力学性能和耐热性能,分析树脂基体对复合材料界面性能的影响。结果表明:国产T800碳纤维表面上浆剂中含有环氧基团。配方优化后的氰酸酯树脂与国产T800碳纤维复合后,复合材料的室温-湿态力学性能保持率大于74.8%,200℃力学性能保持率大于57%,玻璃化转变温度为226℃,具有优异的热机械性能和界面性能。     

水溶性热塑性聚酰亚胺上浆剂对国产高强高模碳纤维复合材料界面性能的影响

以双酚A型二醚二酐(BPADA)、间苯二胺和1,3-二(4′-氨基苯氧基)苯(TPE-R)为原料合成了水溶性热塑性聚酰亚胺上浆剂，对国产高强高模碳纤维(HMCF)表面进行上浆处理并制备成复合材料。研究了不同单体摩尔比对上浆剂特性以及上浆处理后纤维表面结构性能的影响，进一步分析了热塑性上浆剂对国产高强高模碳纤维增强热塑性聚醚酮酮(PEKK)树脂基复合材料界面性能的影响。结果表明，当BPADA与TPE-R的单体摩尔比为1∶1时，合成得到的热塑性上浆剂不仅分子量分布均匀，而且具有优异的热稳定性，如温度554℃其热失重仅为5%。上浆处理后，高强高模碳纤维表面O/C由0.08增至0.18,提高了125%;上浆后纤维强度略有增高，模量几乎无变化；上浆处理后对复合材料界面性能改善明显，HMCF/PEKK复合材料层间剪切强度由处理前38.5 MPa提升至最高59.4 MPa,增幅高达54.3%。     

上浆剂对国产T700级碳纤维复合材料界面性能的影响

采用扫描电镜(SEM)、原子力显微镜(AFM)、X射线光电子能谱(XPS)等测试方法表征了上浆/未上浆国产T700级(MT700)碳纤维的表面特性,并通过单丝断裂实验测试了单丝复合体系微观界面剪切强度(IFSS),在此基础上研究了碳纤维表面特性对单丝复合体系微观界面性能及其耐湿热性能的影响.研究表明:MT700碳纤维表面上浆剂改善了纤维/基体微观界面强度及其耐湿热性能;湿热环境对复合材料的微观界面性能影响显著,尤其是造成纤维/基体间的化学键合作用破坏,去湿后部分界面性能可恢复.     

热塑性树脂基复合材料用碳纤维上浆剂研究进展

与高性能热塑性树脂不匹配、耐热性偏低的传统上浆剂越发难以满足热塑性树脂基复合材料快速发展与应用的需求,开发面向热塑性树脂基复合材料的碳纤维上浆剂具有重要意义。本文对上浆剂的主要作用效果、上浆剂与增强材料和基体树脂间的相互作用、热塑性树脂基复合材料用碳纤维上浆剂的主要特点进行了概述;对聚酰胺、聚氨酯、聚芳醚、聚酰亚胺及其他类型上浆剂的研究进展进行了重点论述,结合各体系的性能特点和主要问题,梳理了不同热塑性树脂基复合材料用碳纤维上浆剂的改性途径及近年来在各大生产企业中的研发应用情况,分析和阐明了各自的作用机制与发展现状,对热塑性树脂基复合材料用碳纤维上浆剂的未来趋势进行了展望,并给出了发展建议。      

炭纤维上浆剂对树脂基复合材料界面性能影响

分析了T300B、T700SC和NCF等不同类型炭纤维上浆剂的结构与性质,研究了上浆剂类型及其含量等对炭纤维/树脂间界面作用的影响.结果表明,不同类型炭纤维表面上浆剂的结构与性质不同,NCF纤维使用的GA#和GB#以及T700SC纤维的5#上浆剂热分解温度较高,优于NCF使用的JF#、T300B纤维的5#上浆剂,其中G...     

磺化聚醚醚酮上浆剂的制备及其对碳纤维性能的影响

目的 制备一种热塑性上浆剂,以期改善碳纤维的表面性能以及单丝拉伸性能。方法 通过直接磺化法制备磺化聚醚醚酮水性上浆剂,并通过喷涂法对未上浆的T300碳纤维进行上浆处理,研究制得上浆剂的结构特征、性能以及其对碳纤维性能的影响。结果 制得磺化聚醚醚酮的磺化度约为74%,以此为主浆料配制的水性上浆剂具有良好的成膜性和储存稳定性。经上浆处理后,碳纤维表面形成了连续的磺化聚醚醚酮上浆层,表面官能团含量明显增加,树脂微滴在纤维表面的接触角降低。此外,上浆层可以弥补纤维表面的部分缺陷,使得上浆后碳纤维的单丝拉伸强度提高了5%。结论 磺化聚醚醚酮上浆剂可以有效改善碳纤维的表面性能及单丝拉伸性能。     

碳纤维表面状态对其复合材料界面性能的影响

为了研究上浆剂和湿热处理对复合材料微观界面性能的影响,通过单丝断裂实验测试去浆处理及湿热处理前后T300、T700SC、T800S碳纤维单丝/环氧树脂体系的界面剪切强度(IFSS),结合扫描电镜测试手段分析了纤维表面物理特性对IFSS的影响.结果表明:去浆及湿热处理均会引起三种单丝复合材料体系IFSS降低,断点形貌由X状向鞘状发生变化,但不同的单丝复合体系IFSS降幅以及断点形貌变化程度不同;去浆后,T700SC/环氧树脂体系IFSS降幅达70.67%,T300/环氧树脂体系仅下降6.05%;湿热处理72 h后,T300/环氧树脂体系IFSS下降幅度最小;湿热作用下,去浆后的单丝/环氧树脂体系IFSS的下降更为显著.     

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.