Which corrosion type occurs along the grain boundaries of a material?

Intergranular corrosion is a specific type of corrosion that occurs at the grain boundaries of a material. This phenomenon typically happens in metals that experience certain conditions, such as improper heat treatment, which can lead to the depletion of alloying elements or the presence of harmful impurities at these boundaries.

In many cases, intergranular corrosion is more prevalent in stainless steels and other alloys that have been sensitized—meaning the material has been exposed to high temperatures that allow chromium carbides to form at the grain boundaries, thus depleting the surrounding areas of chromium which provides corrosion resistance.

Additionally, this type of corrosion can lead to a significant reduction in structural integrity, as it can progress without being readily visible on the surface, making it particularly insidious. Recognizing intergranular corrosion is critical in material selection and maintenance to ensure the longevity and safety of components in various applications.

The other types of corrosion mentioned differ significantly in their mechanisms. Galvanic corrosion occurs when two dissimilar metals are in contact in the presence of an electrolyte, atmospheric corrosion is related to the environmental exposure of a material to the atmosphere leading to oxidation, and filiform corrosion is characterized by a thread-like structure that develops under specific environmental conditions on coated surfaces. Each of