Which method involves preventing electrical contact between dissimilar metals to control galvanic corrosion?

• A. Barrier Coatings
• B. Design
• C. Electrical Isolation
• D. Cathodic Protection

Answer: (C)

Preventing galvanic corrosion relies on stopping the electrical current between two dissimilar metals in an electrolyte. When these metals touch, electrons flow from the more active metal to the less active one, driving accelerated corrosion of the former. Electrical isolation achieves this by using insulating barriers, spacers, or nonconductive coatings that prevent direct metal-to-metal contact and interrupt the electrical circuit. While barrier coatings and other approaches can help reduce corrosion by limiting contact or exposure to the electrolyte, the specific mechanism described is electrical isolation—stopping the electrical connection to prevent the galvanic couple from forming. Cathodic protection changes potentials with an external current rather than preventing contact, and design changes may reduce coupling but don’t inherently guarantee isolation of the electrical path.