Adhesive bonding is a method of bonding materials, which is used in almost every industry, especially in aviation and car manufacturing. In this thesis, we investigated the effect of different surface treatments of adherends on mechanical properties of single lap adhesive bonded joints. Therefore, we cleaned the surfaces of aluminium alloy and stainless steel adherends with isopropyl alcohol, corona discharge plasma and laser. On cleaned surfaces of samples we measured contact angles and surface roughness. Then we bonded cleaned samples with one part epoxy adhesive and tested adhesive joints on tensile test machines. The results of tensile tests showed that surfaces cleaned with isopropyl alcohol and laser produced almost the same shear strengths, while adherends cleaned with corona discharge produced lowest shear strengths. Different surface treatments didn't have any major effect on surface roughness of adherends. The lowest contact angles were achieved on surfaces cleaned with corona discharge. None of the adhesive bonds produced 100 % adhesive or cohesive failure of adhesive and we observed a special cohesion failure as the main failure pattern. On some samples there were voids present because of trapped air in adhesive layer. No correlation between shear strengths, surface roughness and wettability was found.
|
