激光表面处理提高铝合金胶接接头强度的研究

粘接作为重要的汽车轻量化连接技术之一,胶接接头的强度和性能是我们关注的重点,胶接接头的强度和性能完全取决于胶粘剂接触的表面类型,因此在粘接之前对基材表面进行一定处理是粘接工艺中最重要的环节之一。金属的表面处理包括溶剂擦拭、机械打磨、化学清洗和酸蚀。激光表面处理是一种新型绿色环保的表面处理工艺,它可以高速有效的清洁材料表面附着物,并且改变材料表面微观结构及材料表面自由能及浸润性。从而提高粘接接头十字拉伸强度、单搭接拉伸剪切强度和接头耐水性能。通过激光处理,所有接头的破坏形式由界面破坏转为内聚破坏。对铝合金环氧结构胶2098G胶接接头而言,十字拉伸强度、剪切强度和水浴剪切强度,激光处理后比溶剂擦拭分别提高了17.8%,133.8%,88.1%。对铝合金聚氨酯结构胶TS6015胶接接头而言,十字拉伸强度、剪切强度和水浴剪切强度,激光处理后比溶剂擦拭分别提高了698%,225%,223%。激光表面处理有效的使铝合金胶接接头的强度达到胶的本体强度的94%~100%,是铝合金粘接的有效表面处理方法。     

不同表面处理方式对PEEK粘接强度的影响

采用砂纸打磨、喷砂和等离子处理等方式对PEEK进行表面处理,并使用环氧胶进行粘接。通过粗糙度仪、接触角测试仪和万能材料拉伸试验机对PEEK的粗糙度、润湿性和粘接强度等特性进行表征分析。结果表明,不同的表面处理方法对PEEK粘接的性能影响不同。砂纸打磨和喷砂能够有效增加PEEK表面的粗糙度,增大PEEK与粘结剂的粘接面积,从而提高PEEK的粘结强度。而等离子处理能够有效降低PEEK表面的接触角,改善PEEK表面的润湿性,提高PEEK的粘接强度,并且等离子处理后PEEK的粘接强度比未处理、砂纸打磨和喷砂分别提高了600%、260%和110%。     

工艺条件对拉伸试件粘接强度分散性的影响

以铝和丁基橡胶的粘接拉伸试件为研究对象,结合粘接过程被粘面表面处理、涂胶、加压、固化等主要工序,讨论了粘接工艺方式和粘接过程控制对拉伸试件粘接强度分散性的影响。结果表明,在粘接过程中采用适当的表面处理方法、涂胶方式,确定适当的加压压力、涂胶厚度和固化条件,有利于减小粘接件拉伸强度数据的分散性并提高粘接强度。     

铝合金表面阳极化处理及其胶接性能分析

采用磷酸电解质对铝合金板进行了阳极化处理并测试了其胶接性能,测试了阳极化过程中铝合金板的基本力学性能,观察了阳极化处理后的铝合金板的表面形貌,分析了阳极化处理后铝合金粘接副的胶接界面、拉伸剪切失效模式.结果表明,铝合金板经过酸洗、碱洗和阳极化等过程后,其破坏强度、屈服强度、弹性模量和断裂延伸率等力学性能基本保持不变.阳极化后铝合金板表面形成了一层凹凸不平、多孔结构氧化膜,胶接时胶黏剂能渗透进入该氧化膜,形成一层胶接过渡层,阳极化处理提高了铝合金粘接副之间的拉伸剪切强度,其拉伸剪切强度最大可提高1.76倍.阳极化处理后的铝合金板粘接副之间的破坏模式为混合破坏,即存在胶黏剂的剪切破坏,同时存在粘接界面的剥离破坏.     

轨道车辆用特殊材料粘接表面处理技术研究

通过玻璃纤维增强塑料、碳纤维增强塑料、聚碳酸酯、超高分子量聚乙烯和聚四氟乙烯的表面处理工艺对粘接性能影响的研究,找到了特殊材料较佳的表面处理方法,从而提高轨道交通车辆特殊材料粘接接头的粘接强度。     

聚丙烯薄膜与铜箔的粘接

通过聚丙烯薄膜和铜箔的表面处理和胶粘剂的选择,对它们的粘接进行了研究,经胶接接头的剥离强度和耐溶剂性能测试,筛选出粘接强度高、耐溶剂性能良好粘接接头,结果铜箔和聚丙烯薄膜的最高的剥离强度可达到14N/cm,与不经任何处理的空白试样相比,增加近7倍。     

基于有限元法的高分子材料套接胶接结构的研究与应用

套接胶接结构广泛地应用于医疗器械的粘接结构中，为了研究及预测套接胶接结构的强度及失效行为，以医疗器械中常用的三通配件及聚氯乙烯（PVC）管粘接件为例，通过对套接胶接结构的有限元模型的建模，实现粘接接头的失效载荷预测以及进行失效过程中应力的变化及失效行为的研究。结果表明：通过使用TIE约束可将三通、胶层及PVC管体相连接，赋予材料性质后，可较为真实地模拟出测试件实际拉伸及断裂的过程。通过软件中SDEG数值的输出，分析出胶层开始失效的位置及粘接强度下降的原因；通过导出最终失效载荷的数值与位移的关系，分析出随位移的增长粘接强度的变化情况并通过试验验证了预测的准确性。     

粘接非纯剪切计算法的应用

应用粘接非纯剪切计算法对有关资料进行了数据处理,求得了该粘接状态下胶层的拉伸弹性模量E,极限破坏负荷P,极限粘接强度λx=0等一系列特征数据,从而可以进行定量的接头设计.     

胶接失效原因初探及对底胶工艺的再认识

1前言胶接同种或异种材料的过程中，导致粘接失效的因素很多，一般分析失效的方法从四个方面进行，即胶粘剂选用、接头设计、表面处理、粘接工艺。在多年实践中，我们认为应当将上述四个方面综合起来研究，才能找准解决问题的关键。底胶工艺新方法的应用，就是在上述过程中产生的。该项工艺一般认为，其功能仅仅是保护粘接面，防止污染，起到缓冲层作用。从粘合剂界面化学功能归纳，底胶工艺能够保证被粘面耐介质侵蚀的要求。从粘接工艺物理化学功能而言，底胶工艺又能够满足特殊涂胶工艺中表面必须的浸润张力要求。本文试从两则粘接实例阐…     

航空铝合金橡胶金属零件粘接表面处理工艺研究

取5种不同表面处理方法处理的试样进行粘接强度、耐老化、耐油性、耐蚀性能的对比研究。结果表明：经吹砂、硬质阳极化、硫酸阳极化、酸蚀处理后的拉伸试样,其粘接强度、耐老化性能优良,能够满足航空橡胶铝合金零件制造需求。微弧氧化方法处理后的接头,由于选用的胶粘剂特性,抗拉强度较低,其实用性有待进一步研究。     

Sulfonation of polymer surfaces - I. Improving adhesion of polypropylene and polystyrene to epoxy adhesives via gas phase sulfonation

A new method for surface treating polymers and polymer composites based on gas phase sulfonation has been shown to quickly and effectively increase wettability and adhesion to epoxy. A gas mixture containing a low concentration of sulfur trioxide in nitrogen (～ 1% v/v) was used to treat the surfaces of polypropylene and polystyrene films. The sulfonated surfaces were then neutralized with ammonium hydroxide. The effectiveness of sulfonation on the adhesion of these polymers to an epoxy adhesive was investigated using mechanical testing of sandwich lap-shear specimens. The lap-shear adhesive joint strength of epoxy to sulfonated polypropylene was compared with polypropylene treated with currently accepted surface treatments including chromic acid etching and flame treatment. Sulfonation greatly improves the adhesion of polypropylene to epoxy compared with other surface treatment techniques as measured by lap-shear strength. An optimum sulfonation treatment level was shown to exist for polypropylene. For polystyrene surfaces, it was shown that while sulfonation immediately increased wettability, it did not greatly improve its adhesion to epoxy; it did, however, significantly reduce the scatter in the ultimate strength values. Excess sulfonation treatment reduced the lap-shear strength for both polymers. X-ray photoelectron spectroscopic examination of the locus of failure of tested joints has shown that failure occurs in a weak boundary layer for these surface-treated polymers.     

Behavior of adhesively bonded coated steel for automotive applications under impact loads

Novel manufacturing techniques and the application of new materials in the automotive industry increase the challenges in adhesive bonding. One of these is the bonding of coated materials such as high-strength steels with anti-cindering multi layers or painted components. In both cases, the entire build-up of the joint has to be taken into account to determine its strength.Based on common testing methods, i.e. lap-shear or butt-joint tests, this paper presents modifications and possible interpretations of these testing methods for the characterization of adhesive joints of coated materials under impact loading. Another aspect presented here is a laser-based approach for the removal of paint, to achieve higher bond strength. It has been found that the mechanical strength of the bond is influenced significantly by coatings and paints. Furthermore large dependence on the nature of the paint can be found. In general it can be noticed that the weakest layer within the entire joint is the coating or paint. Therefore, these additional layers have to be carefully considered during a product׳s development phase.     

氯丁型胶粘剂拉伸剪切强度的影响因素探讨

主要从胶粘剂测试试件粘接面积、晾胶时间以及干燥和加压等影响因素着手,对氯丁型胶粘剂拉伸剪切强度的测试条件进行了研究与讨论。得出测试氯丁型胶粘剂拉伸剪切强度较为合适的条件。     

Development of metal-bonding spray adhesives for use in aerospace repair applications

In many aerospace applications, the use of film and paste adhesive materials is not conducive to either good manufacturability or good bonding properties. To address this concern, the development of high-performance, epoxy-based, spray-adhesive resins has been undertaken from a research and development standpoint. These materials were investigated in the light of their potential repair applications, with focus on adhesive joint designs based on lap-shear performance and processibility of the adhesive. It was found that the resins investigated displayed adequate lap-shear strengths for the bond types of interest. However, some resins proved to be a considerable challenge during processing and solvent removal presented a problem for some materials. As expected, the combined use of mechanical testing and scanning electron microscopy revealed that the lap-shear strengths of the resins could be tailored with changes in their chemistry, and that these changes also affected the solvent removal process.     

Effect of plasma treatment and electron beam radiations on the strength of nanofilled adhesive‐bonded joints

This investigation highlights the adhesion performance of carbon fiber‐ and glass fiber‐reinforced polyphenylene sulfide when joined by high‐performance neat epoxy adhesive and nanofilled epoxy adhesive. A significant increase in the surface energy of these materials is observed after the surface modification with atmospheric plasma treatment. An increase in surface roughness is observed after exposing the surface to plasma. Lap shear testing of untreated and plasma‐treated joints is carried out to correlate the improvement in adhesion properties with the joint strength. A considerable increase in joint strength is observed when the surfaces of these materials are modified by atmospheric pressure plasma. There is a further increase in joint strength when the composites are joined by nanofilled epoxy adhesive, and subsequent exposure to electron beam radiations results in minor increase in the joint strength. Finally, the fractured surfaces of the joints are examined and the analysis is performed. POLYM. ENG. SCI., 50:1505–1511, 2010. © 2010 Society of Plastics Engineers     

Adhesion of glow discharge polymers to metals and polymers

Adhesion of glow discharge polymers to metals and polymers in an adhesive joint was measured by lap-shear test and immersion in hot water of 70°C °C for an extended time. A glow discharge polymer was deposited onto polymers [polyethylene and poly(tetrafluoroethylene)] and metals (aluminum and stainless steel) prior to when the polymer and metal were joined. It is found that the lap-shear strength is enhanced by coating the surfaces of these substrates with plasma film produced from methane, ethylene, and acetylene, and that deterioration of the adhesive bonding part, when immersed in hot water of 70°C, is strongly dependent on the gas used as well as operational conditions where a polymer film is formed. The adhesion of a polymer produced from methane on the polymer and metal is strong enough to apply for durable, adhesive joints.     

Thin-Disk Test for Adhesion-Bond Strength in Solvent Environments

A number of the popular tests for adhesive strength are difficult to apply to the study of adhesion under solvent environments. Complex applications, in which two different substrate materials need to be bonded and for which the substrates are thin sections, can be particularly difficult to study. The thin-disk test described here uses a thin annular disk of adhesive to bond two dissimilar materials while exposing the bond line to a circulating solvent. The new test was evaluated for a typical inkjet print-head application using surrogates for inkjet water-based inks. The joint is an epoxy adhesive joining a silicon wafer to a thermoplastic part (Rynite®), in which the silicon substrate, the thermoplastic, or the various adhesive interfaces might fail.

A conventional lap-shear test was compared with the thin-disk test for samples exposed to four different solvent systems plus water at two different temperatures. Lap-shear test failures occurred mostly in the thermoplastic part, with the exception of two samples exposed to the most aggressive solvents at high temperature. By contrast, thin-disk test failures occurred either in the silicon substrate or in the thermoplastic–adhesive interface. The thin-disk failure strengths at the thermoplastic–adhesive interface correlated with the equilibrium solvent swelling that could occur in the adhesive under the test conditions. This method could be adapted to other mixed-substrate bonding systems and would be particularly appropriate for thin section solids and thin adhesive layers.     

Influence of Acrylic Adhesive Viscosity and Surface Roughness on the Properties of Adhesive Joint

In adhesion, the wetting process depends on three fundamental factors: the surface topography of the adherend, the viscosity of the adhesive, and the surface energy of both. The aim of this paper is to study the influence of viscosity and surface roughness on the wetting and their effect on the bond strength. For this purpose, an acrylic adhesive with different viscosities was synthesized and some properties, such as viscosity and surface tension, were studied before adhesive curing took place. Furthermore, the contact angle and the lap-shear strength were analyzed using aluminum adherends with two different roughnesses. Scanning electron microscopy was used to determine the effect of the viscosity and the roughness on the joint interface. The results showed that the adhesive exhibits an optimal value of viscosity. Below this value, at low viscosities, the low neoprene content produces poor bond strength due to the reduced toughness of the adhesive. Additionally, it also produces a high shrinkage during curing, which leads to the apparition of residual stresses that weakens the interfacial strength. However, once the optimum value, an increase in the viscosity produces a negative effect on the joint strength as a result of an important decrease in the wettability.     

Strength of resin-coated-adhesive-bonded double lap-shear pultrusion joints at ambient temperature

The inherited adhesion limitation of polyester and vinyl ester resin-based pultruded GFRP makes pultrusions difficult to bond, especially when a thixotropic adhesive is used. While such an adhesive is necessary for gap filling, it has a limited wettability. Therefore, coating the adherend with low-viscosity epoxy resin, prior to bonding, improves wetting and hence increases joint strength. The paper describes the experimental methodology to achieve this, using double lap-shear (DLS) joints with various materials combinations. A significant strength improvement was reached as a result of coating the inner adherend in conjunction with using a “high adhesion” outer adherend. To further understand the effect of coating, numerical stress analysis was undertaken, including preliminary micro-models representing the composite/adhesive interface as well as overall DLS models.