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The influence of chromate, phosphate, glossy and brightening coatings on the performance of adhesive joints of hot-dip zinc-coated steel sheets was compared. The contribution of this study has been to compare the adhesive joint strength in adherends with two types of coatings: steel sheet with zinc coating and additional coating. Two types of bisphenol A (BPA) epoxy adhesives were used to assemble the joints, that were subject to shear stresses. The surface of the adherends was described in terms of surface roughness parameters. The highest value of the shear strength was recorded for the adhesive joints of the hot-dip zinc-coated steel sheets with chromate passivation and brightening. The poorest performing joints were of the glossy galvanized steel sheets.

The aim of this study is to determine the effect of cataphoretic and powder coatings and also the method of application the primer on the adherends surface on the strength and failure modes of EN AW-5754 aluminium alloy adhesive joints. The study is performed on lap joints made of EN AW-5754 aluminium alloy, subjected to three different types of surface treatment; namely a) polyurethane cataphoretic coating, b) powder coating based on black mat RAL 9005 UL polyester resin and c) no coating. The tested adhesive joints were made using a one-component polyurethane adhesive Terostat 8596, which was dedicated for automotive and cured under a constant load of 0.018 MPa at 20 ± 2 °C. In addition, this study investigates the effect of the application of Terostat 8519P adhesion promoter which is a liquid polyurethane-based primer containing solvents and which is corresponding to Terostat 8596 polyurethane adhesive. Terostat 8519P adhesion promoter was applied in two different ways: a) to one substrate and b) to both substrates. The produced adhesive joints were subjected to strength tests using the Zwick/Roell Z150 testing machine. The examination of fracture in the tested adhesive joints was performed in accordance with the EN ISO 10365 standard. The shear strength results have demonstrated that both the method of application of the adhesion promoter (Terostat 8519 P) and the presence of cataphoretic coating had an influence on adhesive joints strength. The use of the adhesion promoter significantly affects the strength of both uncoated EN AW-5754 aluminium alloy adhesive joints and the adhesive joints subjected to powder coating. The use of the adhesion promoter has a less significant effect on the cataphoretic-coated samples.

Among the great number of methods for measuring the surface free energy of solids, all originate in contact angle measurements, which are carried out using various probe liquids, and employ certain relationships and assumptions. Contact angle measurement can be distorted by a number of factors that occur during the measurement and distort obtained values, and therefore must be accounted for. The present work describes the application of the van Oss-Chaudhury-Good approach in determining the surface free energy of aluminium sheets with the use of three probe liquids: water, diiodomethane and glycerol, with assumed values of the surface free energy components. The study employed direct measurement of the contact angle with the goniometer. Subsequently, measurement uncertainty with the van Oss-Chaudhury-Good method was evaluated, which revealed that the major source of uncertainty is the discrepancy between constant values describing properties of probe liquids.

The paper presents the effect of sandblasting on surface properties of steel for adhesion. The investigated parameters included pressure (1, 2 and 4 bars) and four types of abrasive material, each material type being of different granulation. In the experiments the effect of the above variables on the surface roughness, contact angle Θ, work of adhesion W a and surface free energy γ was investigated. It has been shown in this research that surface properties are more affected by abrasive material type applied rather than by the sandblasting process parameters.

This paper examines the effect of a selected environmental ageing condition – specifically the temperature – on the strength of adhesive joints. The joint specimens were formed with EN AW 2024 aluminium alloy sheet adherends bonded with three types of epoxy resin compounds. A novelty in the research is the use of a combination of various types of epoxy resins based on Bisphenol A (BPA) and an amine curing agent dedicated for operating at lower or sub-zero temperatures. The curing conditions for all the assembled adhesive joints were identical, e.g.: temperature 24–26 °C, relative humidity 21 ± 3%, curing time 7 days. The adhesive joints were subsequently subjected to environmental ageing at lower and sub-zero temperatures (−20 °C, −15 °C, 0 °C, 5 °C). The single-lap adhesive joint specimens aged at lower and sub-zero temperatures were placed in the SH 661 temperature and humidity chamber. The reference specimens were subjected to ageing at ambient temperature in laboratory conditions. Upon completion of the ageing cycle, all adhesive joint specimens, including the reference samples, were subjected to shear strength tests on Zwick/Roell Z150 testing machine. According to DIN EN 1465 standard the testing speed was equal to 5 mm/min. The test results indicate that the adhesive joints' strength depends on a number of factors, including the environmental ones. Moreover, the type of an adhesive compound has considerable impact on the adhesive joints’ strength.

We present, for the first time, an original experimental study on the effect of ageing process (seasoned in the aqueous environment) on the mechanical behaviour of adhesive tubular butt joints. In order to manufacture adhesive tubular butt joints, tubes with a diameter of 20 ± 1 mm, made of three different materials (polypropylene, carbon steel and galvanised steel) were considered. Two types of the adhesive epoxy compounds were used, namely a flexible adhesive (Epidian 57/PAC/100:80) and a stiff adhesive (Epidian 57/Z1/100:10). The ageing process, including the adhesive joint samples' seasoning in a specific environment, was conducted using three aqueous environments, namely mineral water, demineralised water and supply water. The specimens were aged for 3 months and 6 months. In addition, one reference sample subjected to the ageing process was considered. After ageing, the samples were subjected to tensile strength tests. These tests were carried out using the ZWICK/ROELL Z150 testing machine in accordance with the norm EN 15870. Based on the test results’ analysis, it was observed that the longer the seasoning time of the adhesive joint samples, the more negative effects on the adhesive joints (decreased strength regardless of the adhesive type or the material). For tubes made of both galvanised and carbon steel, the joints could work well in short-term exploitation as they would keep their strength for a certain period. Such joints could be less expensive in short-term exploitation than the widely used mechanical joints.

The study presents selected problems of the effect of mechanical treatment on surface roughness and adhesive properties as well as adhesive joint strength of steel sheets. In the experiments, the following treatments were applied: grinding, lapping and superfinishing, with variations of some technological machining parameters being taken into account. Based on the conducted experiments, it has been found that the technological parameters of mechanical treatment affect the surface roughness, adhesive properties and adhesive joint strength, depending on the treatment method and parameters applied. It has also been found that the mechanical surface pretreatments have positively affected the adhesive joint strength. The specimens subjected only to degreasing exhibit lower strength.

This article presents the results of the testing of adhesive joint strength of hybrid assemblies consisting of different materials and joints of the same materials. Both experimental testing and numerical FEM analysis of the joints were applied. This type of joint can be found in the aviation industry, for example, where the use of composites as construction materials, including polymer composites with epoxy matrix, is becoming increasingly popular. One frequently used joint type in the aviation industry is the adhesive joint. The literature generally refers to adhesive joints made from the same materials while there is little information on adhesive joints using materials with different geometries and properties (mechanical, physical and chemical), therefore it would be useful to evaluate joint strengths both experimentally and numerically in terms of joint behaviour under various types of load. This paper compares experimental data obtained through numerical analysis for adhesive joints made of titanium sheet, aluminium sheet and aramid–epoxy composite using a number of different joint assemblies.