What is the term for the electrochemical process taking place on the surface of a metal that leads to uniform material loss?

• A. Pitting corrosion.
• B. General attack corrosion.
• C. Galvanic corrosion.
• D. Stress corrosion.

Answer: (B)

Uniform thinning of a metal surface happens when the electrochemical reactions occur across the entire surface, causing the material to dissolve more or less evenly. This is general (uniform) corrosion. The metal’s anodic areas dissolve and the cathodic areas reduce, but the rates are similar over the whole exposed area, so you get a consistent loss of material rather than localized pits.

Pitting corrosion, by contrast, creates small, deep pits in specific spots, not a uniform loss. Galvanic corrosion requires two different metals in electrical contact within an electrolyte, leading to preferential attack of the more active metal. Stress corrosion involves cracking and failure driven by the combination of tensile stress and a corrosive environment.