Strength characterization of adhesive joint surface treated by large-area EB irradiation

With recent improvements in adhesive performance, adhesive joints are being increasingly used in various industrial fields. Despite their advantage of joining dissimilar adherends, adhesive joints are considered unsuitable for key components of mechanical structures due to their large variation in joint strengths. There are many factors that affect the strength of adhesive joints. However, the general bonding mechanisms are (1) mechanical, (2) physical, and (3) chemical bonding. The adhesion mechanism is complex because these phenomena occur simultaneously. Thus, it is necessary to consider these factors separately. Moreover, it is important to understand the bonding mechanism of interfaces in adhesive joints and to improve the reliability of the joint strength. In this study, the tensile strengths of single lap joints were measured to investigate the influence of large-area EB irradiation on strength characterization of adhesive joints. Aluminum alloy plates (A6061) were used as the adherend. Other surface treatments, which were sanding by emery paper, shot blast, and plasma irradiation, were also conducted for comparisons. Each treated surface of the adhered was examined with respect to the surface profile, wettability, and surface analysis by XPS. Results showed that the wettability of treated surfaces of adherend improved, and tensile strength of surface treated adhesive joints was also improved compared with that of the non-treated specimen. Specifically, the strength of the joint with EB irradiation was 1.9 times larger than that of the non-treated specimen. Finally, the effect of large-area EB irradiation on adhesive characterization was discussed.