Durable Sol-Gel Surface Treatment to Control Cathodic Current Density

There are numerous regions across modern aircraft that necessitate advanced corrosion solutions in order to protect and maintain their readiness. One such application is the numerous cathodic fasteners that are galvanically coupled to anodic structural materials, like high-strength aluminum alloys. There is a need to bolster corrosion protection at these locations via a user-friendly surface treatment technology that is extremely durable and easy for maintainer application. To address this critical need, the Luna team will develop a mechanically rugged sol-gel surface treatment for common aircraft fastener materials to limit their cathodic current density. This reduction in available current will result in increased electrochemical protection of the mated aluminum substrate materials, thereby boosting the long-term corrosion resistance at treated interfaces across the aircraft. Specifically, the ambient cure sol-gel surface treatment will be formulated for dip/brush application such that it can be used as both a fastener pretreatment prior to traditional priming, as well as for direct wet installation applications. In this way, the proposed surface treatment will be a drop-in technology for the Navy maintainer and enable application via common techniques and fastener installation practices.