Surface Morphology and its Influence on Adhesion

Abstract

Adhesively bonded airplane structures have sometimes failed in the past. Therefore we started an investigation to look for a comparison between strength and pretreatment of adhesive bonds. Materials used were the common airplane aluminium alloys 2024 T 3 and 7075 T 6 in bare and clad state. The methods of pretreatment were the European CSA-process, the European CAA-anodization, the FPL-process, the PAA-anodization, the SAA-anodization and some Chemoxal-processes. The adhesives we used were FM 123–5 and FM 73, both with primer BR 127. Micrographs from the surfaces prepared by the different treatment methods show, in all cases, a different microstructure which is in some cases more or less suitable for a connection with the polymer structure of the adhesive and, therefore, more or less suitable for good adhesion.