Intergranular and Selective Corrosion
Metals consist of micrometric size crystalline grains. The border between these grains, called grain boundary, is a peculiar and delicate region, due to a distorted crystallographic structure and possible segregation of impurities and second phases. These characteristics of non-equilibrium make grain boundaries particularly reactive, and weaker in terms of corrosion resistance, so that in some cases a localized corrosion, called intergranular corrosion, can occur. This corrosion-type attack is very severe because it leads to grain detachment, then to a reduced mechanical resistance, despite the negligible metal consumption; in some environments and in the presence of tensile stresses it triggers stress corrosion cracking. In this chapter the most common intergranular corrosion forms are described, including stainless steel sensitization, knife-line attack, exfoliation of aluminium, and selective corrosion of brass and cast iron.
- Cihal V (1984) Intergranular corrosion of steels and alloys. In: Materials science monographs, vol 18. Elsevier, AmsterdamGoogle Scholar
- Fontana M (1986) Corrosion engineering, 3rd edn. McGraw-Hill, New YorkGoogle Scholar
- Shreir LL, Jarman RA, Burstein GT (1994) Corrosion. Butterworth-Heinemann, LondonGoogle Scholar