Crevice corrosion can occur where two or more metallic components leave a narrow gap. Common areas for this type of corrosion are on the faces between bolted or riveted structures, the surfaces formed by fasteners and the structure, under gaskets, overlapping faces, etc. Corrosion results from the build-up of aggressive ions in the crevice or oxygen starvation within the crevice. This gives rise to a differential in polarity between the surface and the crevice, whereby the crevice becomes anodic compared to the surface. This type of corrosion can be extremely aggressive and can lead to failure of multiple components in the system.