Galvanic Compatibility Assessment and Prediction in Creviced Atmospheric Conditions

Galvanic corrosion of dissimilar materials is an aggressive form of material degradation that can occur on many modern structures. Naval aerospace components can include the added complexity of occluded regions, from fasteners or faying surfaces, and atmospheric thin-film conditions in high-severity coastal environments.  The combined effects of these environments, geometries, and material combinations can result in aggressive degradation in difficult-to-inspect areas, reducing asset availability and increasing required maintenance costs.  A better understanding of the galvanic compatibility and severity in crevice and atmospheric environment could help inform corrosion-resistant design, material selection, and maintenance planning, increasing asset availability and sustainment of Navy aviation structures. Therefore, in the current effort, a series of computational tools will be developed to predict galvanic compatibility in crevice and atmospheric conditions, based on experimentally-determined electrochemical behavior in the relevant environments.  The laboratory testing and computational tools will build on existing advancements proposed in the recent revision of the MIL-STD-889D. The first computational tool will provide a geometry-independent estimation of the galvanic compatibility, purely based on electrochemical constants extracted from experimental analysis. The second computational tool will use physics-based modeling with experimentally-derived data as boundary conditions in the crevice and atmospheric conditions. The model will produce risk mapping over a component, identifying areas with high corrosion susceptibility. The combination of both tools will provide Navy stakeholders and commercial end-users a rapid assessment of galvanic corrosion susceptibility and distribution in aerospace-relevant environments.