Final answer:
Intergranular corrosion is a type of corrosion that occurs along the grain boundaries of metal due to oxidation. It leads to the degradation of metals and can cause the formation of pits and cracks.
Step-by-step explanation:
Intergranular corrosion is a type of corrosion that occurs along the grain boundaries of metal. When metals crystallize, each seed grows until they meet at the boundaries, and the properties along these boundaries are different from the grains. The separation along the grain boundaries is caused by intergranular corrosion, which is a galvanic process where metals deteriorate through oxidation. This process leads to the degradation of metals and can result in the formation of pits and cracks along the grain boundaries.