Which statement best describes corrosion that occurs uniformly across a metal surface?

• A. General corrosion
• B. Pitting corrosion
• C. Galvanic corrosion
• D. Erosion

Answer: (A)

Uniform corrosion, also called general corrosion, describes material loss that happens evenly over the exposed surface because the environment is uniform and the electrochemical conditions are similar everywhere. When the surroundings are uniform, the entire surface participates in the redox reaction at roughly the same rate, thinning the metal uniformly. In contrast, pitting corrosion creates localized pits where protective layers break down in specific spots, leading to an uneven surface. Galvanic corrosion occurs when two different metals are in electrical contact in an electrolyte, causing the more anodic metal to corrode preferentially at interfaces rather than uniformly across the surface. Erosion involves mechanical removal of material by fluid flow or particulates, which is not a chemical corrosion pattern across the surface.