Electrolytes that form from atmospheric processes can differ widely in composition and thickness and the concentrations of dissolved gases, such as oxygen, in these thin electrolytes vary due to temperature and salinity changes. These changes within the electrolyte can substantially vary the oxidative properties of the electrolyte, which in turn alters the corrosion kinetics of the substrate. In this report, we present an approach for linking measurements of atmospheric properties, such as temperature, pressure, and relative humidity to changes in electrolyte properties, such as dissolved oxygen concentration, film thickness, and salinity. Using Butler-Volmer reaction kinetics, with parameters obtained from fits to polarization data obtained under actual electrolyte thin films equilibrated at different relative humidity values, and bulk polarization measurements, to simulate the electrochemical reactions, we model galvanic corrosion between aluminum and stainless steel alloys, such as UNS A902024 and UNS S13800, in response to changing environmental conditions.

This work was sponsored by the U.S. Naval Research Laboratory under its core research program. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Office of Naval Research, the U.S. Navy or the U.S. government.