Galvanic corrosion is often pronounced when dissimilar materials are in contact and located where?

• A. Near heat sources
• B. In vacuum
• C. Immediately adjacent to each other and at sharp edges or corners
• D. In large uniform areas

Answer: (C)

Galvanic corrosion occurs when two dissimilar metals are in electrical contact in the presence of an electrolyte, forming a tiny battery that drives preferential corrosion of the more anodic metal. It is most pronounced where the metals are in direct contact and the geometry concentrates the current, such as immediately adjacent to each other and at sharp edges or corners. The tight contact and crevices at these points trap moisture and promote higher local current density, accelerating the attack. In contrast, a lack of electrolyte (as in vacuum) prevents galvanic action, and large, uniform areas tend to experience less localized, slower corrosion.