Untersuchung von Lösbarkeitsansätzen für Klebeverbindungen in Metallklebungen

Abstract

The present work focuses on different possibilities for adhesive debonding in metal joints. In particular, a promising method of imbedding additives in the adhesive layer is focused on: The addition of thermally expandable particles (TEPs), which can be activated at a certain higher temperature, leads to weaken the adhesive layer and can thus contribute to an easy debonding. Ti-6Al-4V was used as the metal joint, two different epoxy adhesive systems were compared, and variations were made between different application methods of the adhesive and the TEPs. The application of the adhesive systeme on both sides of the metal substrate and the TEPs by a sieve, proved to be promising and reproducible. Laser treatment of the sample surface resulted in better bonding between adhesive and substrates, compared to untreated samples. Tensile shear strengths, as well as the fracture surfaces were examined and ratet, to identify successful methods and approaches. A concentration of 20-25 wt.% TEPs in the adhesive systeme was found to be the optimum condition for easy debonding, while a lower concentration did not lead to an easy debonding and a higher concentration resulted in higher application deviations. In addition, the specific epoxy adhesive system UHU® Plus Endfest 300 (UHU-Endfest) in combination with the TEPs lead to better results than the E320 epoxy ahesive system. The tensile shear strengths of the laser-treated joints with expanded TEPs with 20-25 wt.% in the UHU-Endfest adhesive system could be reduced by approx. 37% compared to laser-treated joints with the same adhesive system without TEPs. Thus, the use of TEPs in the UHU-Endfest epoxy adhesive system was considered successful for an easy debonding.