Galvanic effects are usually concentrated where the anode and cathode are:

• A. Closest Together
• B. Farther Apart
• C. Separated by Insulator
• D. Not in Contact

Answer: (A)

Galvanic effects arise when two dissimilar metals are in electrical contact in an electrolyte. The current that drives the corrosion tends to be concentrated where the electrical path between the metals is shortest and the impedance is lowest. When the anode and cathode are very close together, the ionic path through the electrolyte is short, so the local current density is high on the anodic surface, leading to concentrated or localized attack there. If they are farther apart, the path is longer and the resistance higher, causing the current to spread out and the corrosion less concentrated. When they aren’t in contact, no galvanic couple forms, so those galvanic effects don’t occur between them.