Which type of corrosion is characterized by localized pits usually accompanied by a white or gray powder?

Pitting corrosion is a form of localized corrosion that occurs when small pits or cavities form on the surface of a metal. It is particularly insidious because it can develop with little or no effect on the surrounding metal, eventually leading to the failure of the material if left unchecked. This type of corrosion typically manifests as small, discrete areas of metal loss and is often indicated by the presence of white or gray powder, which is essentially corrosion products (such as metallic oxides or hydroxides) that form during the corrosion process.

In contrast to other types of corrosion, pitting is highly localized, which means that the affected areas can be quite small compared to the overall surface, making it difficult to detect unless specifically inspected. Understanding the characteristics of pitting corrosion is crucial for maintaining the integrity of aircraft structures and components, as it can lead to significant performance issues.

Other forms of corrosion, such as exfoliation, intergranular, and galvanic corrosion, have distinct characteristics and mechanisms, thus differentiating them from pitting corrosion. Exfoliation generally causes layers of material to lift away, intergranular corrosion affects the grain boundaries of metals, and galvanic corrosion occurs when two dissimilar metals are in contact in a corrosive environment. Each of these