What is "crevice corrosion" and where is it typically found?

Crevice corrosion refers to a type of localized corrosion that occurs in confined spaces where there is limited flow of the electrolyte, leading to stagnant conditions. This often happens in gaps or crevices between two surfaces, such as between a metal surface and a gasket, or in joints and edges of metal structures. The accumulation of stagnant solutions can lead to differences in concentration of corrosive agents within these crevices compared to the surrounding environment. As a result, the localized areas can become more acidic or more corrosive, accelerating the degradation of the metal.

In contrast, the other options describe different types of corrosion. High-temperature environments might lead to other forms of corrosion but do not specifically pertain to the restrictions and localized nature of crevice corrosion. Uniform corrosion occurs over broad surfaces and does not have the concentrated damaging effects typical of crevice corrosion. Lastly, while corrosion on the outer surface of metals exposed to air can occur, it again lacks the localized nature that defines crevice corrosion, which is specific to confined spaces. Thus, understanding crevice corrosion as a phenomenon arising in stagnant regions emphasizes its particularity and importance in materials degradation assessment.