Bonding of Natural Rubber to Steel: Surface Roughness and Interlayer Structure

This paper is concerned with two aspects of the adhesion produced by the vulcanisation bonding of a simple natural rubber (N.R.) compound to mild steel. Adhesion was measured using a 45° peel test.

When the N.R. was bonded, using a proprietary bonding agent (Chemlok 205/220), to 'smooth' steel (acid etched) or to 'rough' steel (phosphated) high values of peel energy (≥ 4.5 kJm^-2), and good environmental resistance to water were obtained, with failure cohesive largely within the rubber. The highest values of peel energy (≈ 7.5 kJm^-2) were associated with a phosphated surface which consisted of plate-like crystals which directed the stresses away from the substrate in a way which produced a failure surface within the rubber which showed extensive tearing and cracking.

The nature of the layer formed in the interfacial region by interaction between bonding system and rubber was investigated using a chlorinated rubber as a 'model compound' representing the adhesive and uncompounded N.R. to represent the rubber. When a blend of the two was heated in air at 150°C, evidence was found of a solid state chemical reaction in which carbonyl groups were incorporated into the blend which became visually homogeneous. Further evidence points to the relevance of this change to adhesion in rubber-to-metal bonding.     

金属与天然橡胶的热硫化粘接

将异氰酸酯分子中的—NCO基团用酚类衍生物加以保护,添加硫化促进剂、高分子成膜剂等,用于金属与未硫化橡胶的热硫化粘接,并对影响粘接的一些主要因素进行了讨论。     

304不锈钢箔的表面处理和粘接工艺研究

研究不同表面处理和胶粘剂实现5μm胶层对0.05 mm厚304不锈钢箔的粘接。试验表明:不锈钢表面粗糙度、偶联处理、胶粘剂和工艺对粘接效果有影响。最佳工艺:不锈钢箔先用丙酮清洗,于刻蚀剂中室温震荡5 min,水和乙醇清洗,再浸泡于浓度为0.5%KH-550乙醇水溶液30 s,乙醇清洗,晾干上胶,保温压粘,不锈钢箔剥离强度可达到9.4 N/cm,并耐丙酮等溶剂浸蚀。     

Aluminium-Aluminium Bonding by Rubber Blend Based on Epichlorohydrin Rubber and Carboxylated Nitrile Rubber

Rubber blends based on epichlorohydrin rubber and carboxylated nitrile rubber can be used as adhesives for aluminium-aluminium bonding. The bond strength depends on blend composition and moulding conditions, such as time, temperature and pressure. Lewis acid/base type interaction is responsible for this type of adhesion. The failure mechanism of the composites was studied by SEM.     

不同金属表面处理对高分子材料与金属连接强度影响

分别利用喷砂、氢氧化钠阳极氧化和激光毛化3种方法对钛合金板进行了表面处理,通过提高其表面粗糙度,来达到提高相应金属–高分子连接件连接强度的目的。其中激光毛化处理能有效提高相应连接件的拉伸性能,而氢氧化钠阳极氧化处理可以有效提高连接件的剥离强度。综合这两种处理方法所制备的金属–高分子连接件的连接强度得到明显提高,拉伸强度为322 MPa,断裂伸长率为5.1%,剥离强度为4.70 N/cm。     

Aluminium-Aluminium Bonding by Rubber Blend Based on Epichlorohydrin Rubber and Carboxylated Nitrile Rubber

Rubber blends based on epichlorohydrin rubber and carboxylated nitrile rubber can be used as adhesives for aluminium-aluminium bonding. The bond strength depends on blend composition and moulding conditions, such as time, temperature and pressure. Lewis acid/base type interaction is responsible for this type of adhesion. The failure mechanism of the composites was studied by SEM.     

Surface Roughness and Particle Adhesion

One of the important mechanisms affecting particle adhesion is the geometry of the contact between the particle and the surface. Atomic force microscopy can measure both this geometry and the particle adhesion. The positional dependence of adhesion of a point probe to a variety of rough surfaces has been measured. The Derjaguin approximation predicts that the adhesion fluctuations are proportional to the surface curvature fluctuations, if the adhesion is dominated by long range forces. Atomic force microscopy adhesion maps have directly verified this linearity.     

Surface Roughness and Particle Adhesion

One of the important mechanisms affecting particle adhesion is the geometry of the contact between the particle and the surface. Atomic force microscopy can measure both this geometry and the particle adhesion. The positional dependence of adhesion of a point probe to a variety of rough surfaces has been measured. The Derjaguin approximation predicts that the adhesion fluctuations are proportional to the surface curvature fluctuations, if the adhesion is dominated by long range forces. Atomic force microscopy adhesion maps have directly verified this linearity.     

NOTE The Application of Surface Analysis Techniques in the Adhesive Bonding of Oily Automotive Steel

There are fewer papers on the adhesive bonding of steel for structural applications than for aluminum and titanium alloys. However, the approach to the adhesive bonding of all three adherends has been similar, that is, the surfaces are pretreated prior to bonding. Trawinski, et al.^1,2,3 reviewed several conversion coatings or etching processes used for steel. Haak and Smith⁴ selected two surface treatments among nineteen based on minimal cost, simplicity and good durability. Smith⁵ has reported work on stainless steel-epoxy bonds under hydrothermal stress. Bischof, et al.⁶ investigated the effect of surface pretreatment of steel on bonding strength obtained with polyvinyl chloride. Ziane, et al.⁷ identified four fracture zones resulting from shear loading of epoxy bonded galvanized steel following four different surface pretreatments. But in some cases, as in the automotive industry, there is a need to bond oily steel directly without surface pretreatment. Rosty, et al.⁸ have reported a study of the role of fillers and cure temperature on the shear strength of oily steel bonded with epoxy. None of the reported research utilizes both microscopic and spectroscopic techniques to analyze the fracture surfaces.     

钢板常温锌系磷化

通过交流阻抗、极化曲线及磷化膜的微观形貌对钢铁常温磷化工艺中温度、pH值、时间进行了研究,确定钢铁磷化的最优工艺。通过交流阻抗、极化曲线、膜的结合力测试、断面形貌分析、析氢腐蚀实验及失重腐蚀实验对基体、磷化膜、磷化钝化膜进行综合性能测试。结果表明:该磷化工艺大大改进了磷化膜的性能,膜厚接近15μm,其硫酸铜点滴实验时间超过3min,磷化膜的阻抗相对基体的提高了近30 000倍,磷化膜以及磷化钝化膜点蚀减小。     

Sulfur Versus Non-Sulfur Containing Polyimide Adhesives for Bonding Steel

Due to their superior thermal and chemical stability, polyimides are often used as adhesives in harsh environments. This study examines the effect on bond strength of thioether sulfur in the polyimide backbone. Bonds were made using steel that was believed to catalyze the oxidation of sulfur. In addition, non-sulfur containing polyimides with similar T_g were also studied for comparison. The polymer/metal interface was studied using both the T-peel and wedge tests. No apparent effect was observed in the T-peel test with steel where the T-peel strengths of non-sulfur and sulfur containing polyimides were similar. In the wedge test, however, the sulfur-containing BDSDA/ODA bonded to steel had the smallest initial crack length of 34 mm. However, the BTDA/APB bonds tested in a dry environment had the smallest crack growth. The sulfur-containing BTDA/ASD performed best of the bonds tested in a wet environment. Metal-catalyzed oxidation of sulfur was observed to take place in the steel case, but not to an extent to have a noticeable effect on peel strength.     

浅析磨料与表面粗糙度的关系

根据海工现场实际情况,介绍了磨料种类选择、磨料大小的选择以及磨料粒度实时监测对粗糙度的影响。     

钢铁表面处理工艺问题探讨

初步探讨了钢铁产品喷涂前处理及静电喷塑的工艺问题。     

基于耐磨性镍磷化学镀层表面粗糙度值的确定

采用镀覆镀层的摩擦轮与铸铁加工的摩擦块在M-2000型磨损试验机上,对具有不同表面粗糙度的镀层及铸铁块施加相同的压应力,以相同的速度进行相同转数的滑动摩擦,记录镀层的磨损量,分析表面粗糙度对镀层耐磨性的影响规律。确定合理的镀层表面粗糙度值为0.4μm。     

浅析表面粗糙度对涂装的影响

根据海工现场实际情况,介绍了表面粗糙度的测量方法,探讨了其对涂层附着力、车间底漆质量、涂料用量的影响。     

涂装前钢材表面处理系列国际标准综述

介绍了涂装前钢材表面清洁度和表面粗糙度评估、表面处理方法以及喷射清理用磨料技术要求等相关系列国际标准。     

涂装前钢材表面处理系列国际标准综述(续)

介绍了涂装前钢材表面清洁度和表面粗糙度评估、表面处理方法以及喷射清理用磨料技术要求等相关系列国际标准。     

基体表面粗糙度对化学镀镍层耐蚀性的影响

基体表面粗糙度影响着化学镀镍层的耐蚀性。使用扫描电镜观察了不同基体表面粗糙度时镀层的表面形貌,采用动电位极化和交流阻抗等技术考察了基体表面粗糙度对镀层耐蚀性的影响。结果表明:当Q345钢基体表面粗糙度为1.81μm时,表面沉积的Ni-P化学镀层的胞状物大小不一,镀层的平整性差,自腐蚀电流密度大,腐蚀速率相对较高;当基体表面粗糙度下降到0.39μm和0.17μm时,镀层表面胞状物的大小趋于一致,且镀层的平整性提高,镀层更容易发生钝化,自腐蚀电流密度下降,耐蚀性得到了改善。     

钢材表面处理检查

防腐蚀涂料涂装的基础工作是表面处理,包括结构缺陷修正、除油、打磨、喷射抛丸清理等多种方法。介绍了表面处理过程中质量检查的内容和方法,以及相关的标准规范等。     

Effect of Surface Roughness on Retention of Reverse Osmosis Membranes

The performances of two commercially available Thin Film Composite reverse osmosis membranes i.e. TFC-ULP and TFC-SR2 from Fluid Systems were studied. For the TFC-ULP membrane low water flux (around 7 lit/m²·h) and high ion retention (around 70%) were obtained. However the TFC-SR2 membrane showed much higher flux (90 lit/m²·h) and much lower retention (around 15%).Unlike the common membranes, TFC-ULP and TFC-SR2 membranes are composed of three layers. The skin layers of both membranes are made from polyvinyl alcohol and the two support layers are made from poly aryl sulfur ether and polyester. However contradictory behaviors of the membranes cannot be explained by the characteristics of materials used for membrane preparation and/or membrane morphology.Scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed that the TFC-ULP membrane possesses a rough surface while the TFC-SR2 membrane predominantly has a smooth surface. Contradictory membrane performances may be due to higher trapping of the ions on the rough surface of TFC-ULP membrane resulting in higher retention. The deposition causes higher resistance against the flow leading to lower flux. The smooth surface of the TFC-SR2 membrane has less ability to trap the ions resulting in lower retention, lower resistance against the flow and therefore higher flux.