Which environment leads to high rates of uniform corrosion in aluminum?

• A. Seawater
• B. Acidic
• C. Alkaline
• D. Neutral

Answer: (C)

Aluminum’s resistance often comes from its protective oxide layer, which keeps uniform attack low. In strongly alkaline environments, this oxide behaves differently: the base promotes dissolution of the oxide film, forming soluble aluminates. With the protective barrier removed across the whole surface, the metal corrodes uniformly rather than in localized pits. That’s why alkaline conditions drive high rates of uniform corrosion for aluminum.

In seawater, chloride ions tend to cause localized pitting rather than uniform thinning; neutral environments let the oxide film stay largely intact, and acids can attack differently but don’t produce the same widespread oxide dissolution as strong bases.