Corrosion is an important subject in materials engineering and of enormous concern to the industry, primarily because of the huge direct and indirect economic loss due to corrosion. The process of crevice corrosion is similar to pitting corrosion. Exception is that, it occurs in the very narrow gaps between faying surfaces, the surfaces that are closely connected and thus unable to be inspected without dismantling, where the solution concentrates by capillary or other action.

For example of the faying surfaces, the surfaces within riveted joints or between bolt or rivet heads and the metal being fastened. Faying or fayed is a term that originated in wood shipbuilding indicating a very close joint between timbers.

Some moisture evaporates. The remaining solution trapped in the crevice, which becomes stagnant and increasingly corrosive. (Moisture deposited on metal will absorb carbon dioxide, CO2 from the atmosphere and form a mild carbonic acid, H2CO3 which increases the electrolytic function).

Crevice corrosion is often brought about by poor sealing or protection practices when applying/rinsing off acid etch cleaning solutions prior to painting. If dust containing salt is allowed to remain trapped in joints hygroscopic action (the term hygroscopic describes substances that absorb atmospheric water) will eventuate in a corrosion cell. Water staining found between bundled and stored aluminium sheets is a form of crevice corrosion.