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1986
Journal Article
Titel
Adhesion in bonded aluminium joints for aircraft construction
Abstract
The aluminium alloys and adhesive currently employed in aircraft construction have been used to investigate, using a variety of experimental techniques, the fundamental characteristics of structural bonded aluminium joints, with particular emphasis on the boundary layer zone. The results of studies on the individual components of the joint are first described in order to assess the interdependent influence of each component in subsequent ageing tests of the entire bonded joint. Substantial knowledge is presented as a result of these investigations concerning the long-term durabiltiy of bonded aluminium joints, and two degradation mechanisms have been elucidated. These are: (1) an alkaline course of destruction caused by the influence of moisture on the aluminium oxide in epoxy resin systems; and (2) an acidic degradation which can only occur alongside electrochemical corrosion of the metal. For sheet metal to sheet metal joints produced according to current regulations, only the acidic mechanism, so-called bondline corrosion, is of utmost technical importance. By explaining the factors influencing joint durability, fundamental adhesion principles are highlighted from which proposals for improvements are made and topics for future optimization research are suggested.