Intergranular Corrosion

Preferential chemical or electrochemical attack that progresses along the grain boundaries of a polycrystalline material because those boundaries differ in composition or microstructure from grain interiors.

A form of corrosion that preferentially attacks and advances along the grain boundaries of a polycrystalline metal or alloy, often because boundary regions have a different local chemistry or electrochemical potential than grain interiors, producing structural weakening without uniformly deep surface loss.