Which area is most closely associated with corrosion that occurs when different metals are in contact within fastener regions?

• A. Piano Hinges
• B. Water Entrapment Areas
• C. Rocket & Gun Blast areas
• D. Magnesium Surfaces

Answer: (A)

Galvanic corrosion happens when two dissimilar metals are in direct electrical contact in the presence of moisture, creating a tiny electrochemical cell that accelerates corrosion of the more anodic metal. In fastener regions, you often have different metals meeting—such as aluminum skin with steel or other metal hardware—especially in hinges where joints can trap moisture and salt solutions. Piano hinges are a classic area where these dissimilar metals meet and moisture can accumulate, making them a prime site for this type of corrosion. The other areas aren’t specifically defined by dissimilar-metal contact at fasteners, so they’re less related to this corrosion mechanism. To prevent it, use compatible materials, proper coatings or isolators, and design to avoid water entrapment around fasteners.