Which statement correctly differentiates galvanic corrosion from crevice corrosion?

Which statement correctly differentiates galvanic corrosion from crevice corrosion?

• A. Galvanic corrosion occurs when dissimilar metals are electrically connected in an electrolyte; crevice corrosion occurs in stagnant, confined spaces due to localized chemistry.
• B. Galvanic corrosion occurs in stagnant spaces; crevice corrosion occurs with dissimilar metals in electrolyte.
• C. Galvanic corrosion is caused by heat; crevice corrosion is caused by cold.
• D. Galvanic corrosion only occurs in vacuum; crevice corrosion only in air.

Answer: (A)

Galvanic corrosion happens when two different metals are electrically connected in an electrolyte. The metal with the higher reactivity acts as the anode and dissolves, while the other metal serves as the cathode and is relatively protected. Crevice corrosion, on the other hand, is a localized attack that occurs in confined, stagnant spaces where the chemistry becomes highly uneven—the small crevice traps solution, oxygen is depleted, and aggressive ions accumulate, driving corrosion in that spot. So the best statement ties galvanic corrosion to dissimilar metals in an electrolyte and explains crevice corrosion as a result of stagnant, confined spaces with localized chemistry. The other descriptions mix up the conditions (stagnation vs dissimilar metals, heat/cold, or vacuum vs air) and don’t capture the distinct mechanisms.

Galvanic corrosion happens when two different metals are electrically connected in an electrolyte. The metal with the higher reactivity acts as the anode and dissolves, while the other metal serves as the cathode and is relatively protected. Crevice corrosion, on the other hand, is a localized attack that occurs in confined, stagnant spaces where the chemistry becomes highly uneven—the small crevice traps solution, oxygen is depleted, and aggressive ions accumulate, driving corrosion in that spot.

So the best statement ties galvanic corrosion to dissimilar metals in an electrolyte and explains crevice corrosion as a result of stagnant, confined spaces with localized chemistry. The other descriptions mix up the conditions (stagnation vs dissimilar metals, heat/cold, or vacuum vs air) and don’t capture the distinct mechanisms.