Which term best describes the peeling away of metal layers caused by corrosion along grain boundaries?

Which term best describes the peeling away of metal layers caused by corrosion along grain boundaries?

• A. Uniform Surface Corrosion
• B. Pitting
• C. Intergranular Corrosion
• D. Exfoliation Corrosion

Answer: (D)

Exfoliation corrosion is the process you’re describing: corrosion that loosens and removes layers of metal from the surface, causing sheets or flakes to peel away along the grain boundaries. This happens when the attack along grain boundaries weakens the interfaces enough that the surface layers separate and lift off, often forming visible flakes. That layered peeling is the defining feature, setting it apart from intergranular corrosion (which occurs along grain boundaries but doesn’t necessarily produce peeled layers), pitting (localized pits), or uniform surface corrosion (even thinning rather than peeling).

Exfoliation corrosion is the process you’re describing: corrosion that loosens and removes layers of metal from the surface, causing sheets or flakes to peel away along the grain boundaries. This happens when the attack along grain boundaries weakens the interfaces enough that the surface layers separate and lift off, often forming visible flakes. That layered peeling is the defining feature, setting it apart from intergranular corrosion (which occurs along grain boundaries but doesn’t necessarily produce peeled layers), pitting (localized pits), or uniform surface corrosion (even thinning rather than peeling).