α-Al2O3陶瓷膜管与金属粘接强度的实验研究

以粘接方法,选用4组新型耐腐蚀、耐酸碱、耐高温胶粘剂对高纯α-Al2O3陶瓷膜管与20#钢进行连接,在常温下对粘接试样进行了拉伸剪切强度测试,在此基础上选择2组实验结果较好的粘接试样,分别在250℃、400℃、550℃、700℃下进行拉伸剪切强度测试。大量的测试数据显示,α-Al2O3陶瓷-金属粘接试样在常温、高温下均能够达到较高的拉伸剪切强度,且随温度升高试样的粘接强度先下降后上升。     

EVA/金属复合材料界面及VA含量对其拉伸剪切强度的影响

利用X射线光电子能谱分析了乙烯-乙酸乙烯共聚物(EVA)/Al,EVA/Cu复合材料的界面,测试了不同乙酸乙烯(VA)含量的EVA/Al,EVA/Cu复合材料的拉伸剪切强度。结果表明:EVA与金属复合的界面大多是羰基与金属相互作用的结果;VA含量低时,随着VA含量的增加,与金属反应的羰基数量也会增加,EVA/金属复合材料的拉伸剪切强度也随之增加。但VA含量超过一定程度后,EVA本身的强度下降,从而造成EVA/金属复合材料的拉伸剪切强度整体降低。     

结构胶粘剂的橡胶改性

引言作为结构胶粘剂基本树脂的结构型热固性聚合物,具有模量高、质地脆,无延伸性等特点。结构胶粘剂的接头多半被设计成与图1(a)所示的搭接剪切试样相似。乍看起来,试样中的胶粘剂似乎只承受剪切负荷。假若它承受的只是剪切负荷,那么胶粘剂的脆性只能在冲击     

CRH3高速动车组空调通风口胶接结构设计

通过理论分析和计算确定了动车组空调通风口部件与铝合金车体胶接用胶粘剂的强度指标。介绍了胶粘剂的选择及胶接结构的设计原则,考查了搭接长度、搭接宽度、胶层厚度和被粘接材料厚度等对胶接件粘接强度的影响。结果表明:车体与空调通风口部件的胶接接头选择受剪切应力作用的搭接接头较适宜,并且搭接接头的承载能力随搭接长度或宽度增加呈先快速上升后趋于稳定态势;当搭接长度为10 mm、胶层厚度为6 mm、铝合金板厚度为5 mm且常温湿固化型单组分PU(聚氨酯)胶粘剂的剪切强度超过0.23 MPa时,搭接接头的承载能力相对最大。     

氧化铝增强混杂纤维复合材料传动轴微波固化性能研究

为了提升微波固化成型复合材料传动轴的承载能力,提出了采用混杂纤维作为增强体,氧化铝颗粒增强环氧作为基体的材料增强方法,同时进行微波固化工艺的优化。通过对比平板试样的层间剪切、拉伸以及动态冲击性能,确定最优体积混杂比、氧化铝含量及微波固化参数。在此基础上,通过织物湿法缠绕制备传动轴缩比件,基于轴的弯曲和扭转试验,对比热固化和微波固化的性能差异等。结果表明:(1)利用低功率预热结合高功率固化,可以在保证固化效率的前提下,提高试样的层间剪切强度;(2)随着碳/玻混杂比的增加,在试样层间剪切和面内拉伸性能增加的同时,伴随着冲击韧性的降低;(3)随着氧化铝含量从0增加到30%,试样的层间剪切强度、拉伸强度和模量分别提升了8. 7%、27. 9%和12. 5%,含量进一步增加会造成性能降低;(4)热固化和微波固化得到的复合材料传动轴身管的最大扭矩、弯曲强度/模量性能处于同一水平。     

纳米复合胶粘剂的合成与性能

用溶液聚合法合成了一系列丙烯酸乙酯（EA）、丙烯酸丁酯（BA）和丙烯酸（AA）的二元和三元共聚物。分别用溶胶-凝胶法和溶解混合法制得了丙烯酸酯共聚物和二氧化硅或粘土的纳米胶粘剂。在铝（Al）、木材（W）和双向拉伸聚丙烯（PP）这三种不同表面性能的基材上，用测定剥离强度、搭接剪切强度和静态剪切强度的方法，考察了纳米粒子对复合胶粘剂性能的影响。研究发现，随着聚合物极性的增加、纳米填料含量的增加，铝-铝和PP—PP粘接件的剥离强度显著提高，这是由于纳米胶粘剂具有更高的附着强度。对于纯丙烯酸酯胶粘剂，测试时的破坏部位在界面处，而对于纳米胶粘剂，其破坏的性质为粘-滑断裂。纳米胶粘剂的搭接剪切强度和静态剪切强度均随纳米填料含量的增加而增大。由于基材表面羟基基团存在的相互作用，因此，铝-铝和木材-木材显示出的粘接强度较高。     

胶黏剂拉伸剪切强度试验方法分析

介绍了国内外胶黏剂拉伸剪切强度的试验方法。分析了国内外试验方法试样尺寸、试验速度、夹持距离和搭接长度等参数的异同点,以及不同参数对试验结果的影响。     

端羧基液体橡胶增韧环氧树脂结构胶剪切强度影响因素的研究

主要讨论了环氧树脂结构胶粘剂搭接拉伸剪切强度的影响因素。通过实验发现,端羧基液体橡胶(CTBN)用量、基材表面处理、填料种类及用量都将对剪切强度产生显著影响;采用20份CTBN作增韧剂,6份纳米二氧化硅作填料,同时对基材进行表面氧化处理时,胶粘剂的剪切强度可达25 MPa。     

天然橡胶/丁苯橡胶-金属热硫化黏合剂的研制

以氯丁橡胶(CR)、多苯基多亚甲基多异氰酸酯(PAPI)、环氧树脂(EP)和混合溶剂等为主要原料,制备了天然橡胶/丁苯橡胶-金属热硫化黏合剂。研究了CR掺量、PAPI掺量、EP掺量、硫化温度和硫化时间等对黏合剂拉伸剪切强度的影响,并探究了EP和PAPI的反应机制。研究结果表明:随着PAPI、CR或EP掺量的增加,黏合剂的拉伸剪切强度呈先升后降态势;当硫化温度为150℃、硫化时间为15 min时,黏合剂的综合性能相对最佳,其拉伸剪切强度为1.40 MPa、橡胶的拉伸强度为11.8 MPa,并且试样的破坏形式均为橡胶内聚破坏。     

胶层厚度对环氧胶粘剂使用环境下力学性能影响的试验研究

为了研究不同厚度胶粘剂在其使用环境条件下对力学性能的影响,从两种金属结构环氧胶粘剂中各挑选了两种厚度的胶粘剂,并在不同的使用环境下研究不同胶层厚度对剪切强度、剥离强度、平面拉伸强度和蠕变的影响。研究结果表明:在高低温环境、湿热环境、JP-4燃油浸泡处理的试样件剪切强度、平面拉伸强度性能以及蠕变试验中,0.3 mm的胶层厚度比0.6 mm胶层厚度对胶粘剂的力学性能影响大;在盐雾环境、阻燃液压油浸泡处理的试样件剪切强度以及蜂窝剥离强度试验中,胶层厚度对胶粘剂力学性能的影响不明显;在3型试验液浸泡处理的试样件剪切强度以及滚筒剥离强度试验中,0.6 mm的胶层厚度比0.3 mm胶层厚度对胶粘剂的力学性能影响大。     

金属与金属化合物超细粉体的微孔过滤

叙述了金属与金属化合物超细粉体与液体过滤中的若干问题,主要介绍了有关过滤精度、滤速等计算方法,最后简单介绍了可用于过滤和洗涤的两种高分子精密微孔过滤机。     

Treatment of Synthetic Crudes with Metal Chlorides and Metal Carbonyls

Abstract

The removal of problematic synthetic crude compounds with limited amounts of transition metal chlorides, carbonyls and hydrido carbonyls was investigated. A middle distillate fraction containing pure compounds of nitrogen and sulphur that are typical of this fraction was used. Chlorides of copper, iron, tin and zinc showed significant potential for removal of the nitrogen compounds and ethyl and phenyl mercuric chlorides reacted with these compounds at 200[ddot]C. These chlorides reacted with mercaptans and alkyl sulphides to varying degrees and with the exception of ethyl mercuric chloride had little effect on benzo and dibenzothiophene. However, the carbonyls of cobalt and manganese were quite promising for these thiophenes. Hydrido carbonyls of these metals were more favourable for the nitrogen compounds. There is evidence of competition for sites on the solid metal salts.     

扩散焊接异种金属及陶瓷/金属的研究进展

扩散焊接作为一种新颖的焊接技术之一,在异种材料的连接领域得到了广泛应用.本文在综述扩散焊接原理和特点的基础上,着重介绍了扩散焊接在异种金属、陶瓷/金属异种材料连接中的应用及研究现状.     

Metal Particle Size Determination of Supported Metal Catalysts

The variety of supported metal catalysts utilized in the operations of the petroleum and chemical industries emphasizes the importance of metal-catalyzed reactions. As a result, many scientific investigators have attempted to characterize and follow closely the changes in the crystallite size and shape of supported metal particles in commercial and simulated environments. From these efforts a massive production of experimental facts has emerged.     

Metal Particle Size Determination of Supported Metal Catalysts

The variety of supported metal catalysts utilized in the operations of the petroleum and chemical industries emphasizes the importance of metal-catalyzed reactions. As a result, many scientific investigators have attempted to characterize and follow closely the changes in the crystallite size and shape of supported metal particles in commercial and simulated environments. From these efforts a massive production of experimental facts has emerged.     

金属表面处理工艺对橡胶与金属粘合性能的影响

研究了金属表面处理中抛丸工艺，磷化工艺对橡胶与金属的粘合强度的影响。取得了相应的最佳工艺参数，用扫描电镜进行观察。证实了所提出的观点。     

52919离子色谱法测定烟叶中的过渡金属和重金属

采用非抑制型离子色谱法、阳离子交换柱、电导检测器,以柠檬酸-苹果酸-乙二胺为淋洗液,同时测定Ag 、Cu2 、Cd2 、Zn2 、Pb2 五种离子.研究了淋洗液配比及淋洗液pH对分离效果的影响,选择了最佳分离条件,得出五种离子的工作曲线方程,相关系数为0.989～0.999,检出限为0.02～0.1 μg/mL,RSD为1.64%～4.03%,样品加标回收率为98%～104%.本方法用于烟叶样品的分析,具有简便、快速、检出限低,灵敏度高,准确度高、选择性好的特点.     

Metal pelleting and cooling

Pelleting is a process of conditioning, compacting, and extruding a finely divided material resulting in larger particle sizes with greater bulk density and improved flow characteristics in which dust is essentially eliminated. The process has a relatively short history beginning in 1929 with the conception and design of equipment using the die and roller principle. Conditioning is accomplished by the use of good quality steam added at a controlled rate to a regulated flow of material in a paddle type mixer integrally mounted on the pellet mill. This steam adds heat and moisture to enhance the pelleting characteristics of the material. Compaction is accomplished by the action of the rolls upon the die face which also supplies the force necessary to extrude the material through the die holes thus forming pellets. In the pelleting of oilseed meals the sizes of pellets are generally limited to 1/4 in, diameter for export with 1/4 in., 3/4 in., and 7/8 in. being quite common for animal feeding. Many times the 3/4 in. or 7/8 in. pellets are broken through crumbling rolls to form a coarse, granular product. A cooling and drying step is necessary following the pelleting process to remove heat and excess moisture to result in a stable product. This step is accomplished by the use of either a vertical or horizontal cooler by means of which ambient air is drawn through a moving bed of pellets. Exhaust air from this process must be discharged to atmosphere through an efficient cyclone collector to remove entrained dust and feed particles. Following the cooling step the pellets are usually screened to remove the particles smaller than the pellet, thought in the export trade this step may be eliminated. It is desirable to remove extraneous material from the feedstock ahead of the pellet mill in order to protect the dies and rolls. This is accomplished by magnets in the case of magnetic materials and high capacity centrifugal screeners for nonmagnetic materials. In the case of solvent extracted meals with a very low residual oil content, it is usually customary to blend back refinery residues to supply a small amount of oil to enhance pellet quality and equipment capacity. Various oilseed meals exhibit different pelleting characteristics resulting in a wide variation in pellet mill performance.     

金属磷化技术

综述了磷化发展的状况、磷化膜的分类,并阐述了磷化的原理。     

Multinuclear Metal Carbonyl Alkoxide and Aryloxide Derivatives as Models for Metal Carbonyls Adsorbed on Metal Oxide Supports

The synthesis and characterization of two tungsten carbonyl dimers containing bridging alkoxide or aryloxide ligands are described. The crystal and molecular structures of [PPN]₂[W₂(CO)₈(OCH₂CF₃)₂], 1, and [Et₄N]₃[W₂(CO)₆-(OPh)₃]-CH₃CN, 2 , are reported and compared with the structures of tetranuclear tungsten derivatives previously described. The dimer 1 crystalizes in the triclinic space group P 1 with unit cell parameters a = 13.460(11) Å, b = 12.318(5) Å, c = 13.842(10) Å, α = 82.73(5)°, β = 59.11(5)°, γ= 80.09(5)°, V = 1938(2) ų, and Z = 1. The complex 2 crystalizes in the monoclinic space group P2₁/n with unit cell parameters a = 11.954(2) Å, b = 19.359(4) Å, c = 26.462(5) Å, β = 102.50(16)°, V = 5979(2) ų, Z = 4. Molecular modeling software was utilized to construct a tetranuclear derivative from 1 similar to the structurally characterized [W(CO)₃OH]₄₋⁴ tetramer. The two tetramers were found to possess similar molecular parameters. This supports the contention that dimers of type 1 are the precursors of the tetramers. Comparisons of the tungsten alkoxides and aryloxides with the behavior of W(CO)₆ on γ-alumina are provided.