ABSTRACT
Examples of adhesive bonding as a manufacturing process can actually be traced back as far as 3000 B.C. according to Dietz (20). Bonding was a method for joining individual components to form more complex structures when most mechanical and fusion methods of joining had yet to be devised. The late arrival of aluminum into the marketplace meant its particular history of joining has had to be a relatively recent development. The need for bonding aluminum aircraft was obviously a major accelerator of the technology. The need for better aircraft performance has made improvements in the state of the art mandatory. Nevertheless, riveting of aluminum has remained as the major procedure in aircraft fabrication, as demonstrated by the profusion of mechanical fasteners that are still seen on existing aircraft surfaces. The control and inspection of riveted structures has continued to offer support to the use of the metal fasteners but we are now encountering ever more serious problems in the sensitivity of steadily aging aircraft to fatigue failure. The possibility that bondments could be more resistant to such fatigue failures seemed to be confirmed in the middle 1970s by the completion of the U.S. Air Force research program titled Primary Adhesive Bonded Structure Technology (PABST). There has, therefore, been increasing use of adhesive bonding of both primary and secondary aircraft structures. A better understanding of the surface properties of aluminum and how those surfaces interact with adhesive polymers is most pertinent to the present and future developments in aerospace and general manufacturing technologies.
