2018/08/23 by Veronica N. Rafla, John R. Scully
Engineering · Materials Science · #Advanced Welding Techniques Analysis #Aluminum Alloy Microstructure Properties #Corrosion Behavior and Inhibition
paper · doi:10.5006/2885
crossref issued 2018/08/23 · crossref published 2018/08/23 · crossref published-online 2018/08/23 · openalex publication_date 2018/08/23 · crossref created 2018/08/23 · crossref published-print 2019/01/01 · crossref deposited 2025/03/18 · openalex created_date 2025/10/10 · crossref indexed 2026/07/27 · openalex updated_date 2026/07/28
Dissimilar metal coupled multi-electrode arrays (CMEAs) of AA7050-T7451 and Type 316 stainless steel were utilized to investigate galvanic coupling behavior under atmospheric conditions, represented by thin electrolyte films and wet/dry cycling. CMEAs were used to analyze location specific galvanic current densities under both a simple flat geometry and in a simplified two dimensional (2D) representation of a fastener geometry. Cyclic wet/dry exposures on the flat CMEAs under 70 μm thin films increased the anodic charge density by over one order of magnitude relative to the 70 μm exposure of a flat CMEA under constant 98% relative humidity. During the wet/dry cycle, sharp current increases were observed upon the onset of wetting and drying attributed to the high Cl− concentration in the droplet and thin electrolyte layer. Using a CMEA arranged to represent a 2D representation of a fastener in a plate, the anodic charge for galvanic corrosion currents increased under a static 70 μm thin film of NaCl solution wicking throughout the crevice relative to a flat geometry CMEA under full immersion. Moreover, anodic currents were higher at mouth of the fastener as well as deep inside the fastener-plate crevice. CMEAs indicated that the confined space created by the fastener plate arrangement combined with wet/dry cycling increased galvanic corrosion charge almost 10-fold compared to a flat CMEA geometry under full immersion. This occurred despite possible oxygen depletion and lack of anode and cathode separation within the crevice.