Intergranular Corrosion

Intergranular corrosion attacks the interior of metals along grain boundaries. It is associated with impurities which tend to deposit at grain boundaries and/or a difference in phase precipitated at grain boundaries. Heating of some metals can cause a “sensitization” or an increase in the level of inhomogeniety at grain boundaries. Therefore, some heat treatments and weldments can result in a propensity for intergranular corrosion. Susceptible materials may also become sensitized if used in operation at a high enough temperature environment to cause such changes in internal crystallographic structure.