In which environment do the electrolyte resistance limit galvanic effects to the area around the contact?

• A. Atmospheric Exposures
• B. Immersion
• C. Vacuum
• D. High Temperature

Answer: (B)

Galvanic corrosion only occurs when ions can move through an electrolyte between two dissimilar metals. How far the corrosion current spreads depends on the resistance of that ionic path. When the electrolyte provides a relatively high resistance, the current is limited, so the strong galvanic activity stays localized near the contact point rather than propagating across a larger area. In an immersion environment, the metals are surrounded by electrolyte, and the local conditions at the immediate contact dominate the current flow, keeping the galvanic effects concentrated around where the metals meet. In environments with little or no electrolyte (like vacuum) or with conditions that lower the electrolyte resistance, the current paths and corrosion distribution would be different, so the localization described here is most characteristic of immersion.