Another name for crevice corrosion?

• A. Galvanic corrosion
• B. Concentration cell corrosion
• C. Uniform corrosion
• D. Pitting corrosion

Answer: (B)

Crevice corrosion is driven by a difference in reactant concentrations inside a confined gap. In a crevice, the solution becomes depleted of oxygen and can accumulate metal ions and chloride, so the conditions inside the crevice differ from those outside. This creates a small electrochemical cell where the metal at the crevice base dissolves (anodic reaction) while the area with more oxygen outside acts as the cathode. Because the driving force is a concentration gradient rather than two different metals, this is best described as concentration cell corrosion. The other options involve different scenarios: galvanic corrosion requires two dissimilar metals in contact; uniform corrosion is a widespread, even attack; and pitting corrosion is another form of localized attack due to passive film breakdown, not specifically the crevice-driven concentration gradient described here.