This paper, written as part of an ongoing collaboration between BTG, Southwest Research Institute, and Lockheed Martin Skunkworks. Funded by the Defense Advanced Research Projects Agency (DARPA), the collaborators examine and develop techniques for engineering a certifiable bonded method for aircraft manufacturing. The use of composites is increasingly employed in aircraft manufacturing to replace titanum and aluminum. However, composites weaken by the use of fasteners such as bolts and rivets. This is where the implementation of adhesives comes in. The understanding of surfaces requires knowledge on how an adhesive will stick to the surface and the presence of contaminants.
A New Approach
Studying the effects and habits of contaminants can be an essential step in any bonding or adhesion process as a contaminant can significantly influence the success of an adhesive or bond. All surfaces contaminate upon exposure, making them inevitable to any process. Thus, understanding the relationship between a contaminant structure and the effect it has on a bond will help develop more productive monitoring procedures for preparation processes, stronger adhesives and coating formulations, and more reliable construction.
The current method to evaluate the effect of contaminants on a surface entails examining a complex cocktail of them. However, not all contaminants in the blend might exist in a given manufacturing environment. The cocktail method fails to inform us of the effects an individual contaminant will have on a surface.
This article proposes a new method for evaluating the detrimental effects of surface contaminants. It suggests grouping together individual components of a wide range of contaminants into categories based on chemical structure. Consequently, this study allows the prediction of the effects of new, untested contaminants. By understanding the relationships between individual contaminant structure and composition, and its effect on adhesive coating and performance, adhesive processes and surface preparations will become more efficient and effective.
White Paper: A New Approach for the Evaluation of the Effects of Contaminants on Surface Sensitive Processes
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