Crevice Corrosion
Definition
Corrosion in confined geometry , under gaskets, at lap joints, between fastener and plate , driven by oxygen depletion and acidification inside the crevice.
- Location
- Confined geometry: gaskets, lap joints, fastener-plate contact
- Driver
- Oxygen depletion and acidification inside crevice
- Category
- Localised corrosion failure mode
Common questions
Why does oxygen depletion inside a crevice actually drive corrosion rather than prevent it?+
The oxygen-starved region inside the crevice becomes anodic relative to the oxygen-rich surface outside it, and this differential aeration cell concentrates metal dissolution and acidification inside the confined space rather than spreading it evenly.
How can crevice corrosion be distinguished from general surface corrosion during failure analysis?+
It appears as localised pitting or attack specifically at gasket faces, lap joints, and under fasteners, while the surrounding open surface remains comparatively unaffected, which points to a geometry-driven mechanism rather than uniform environmental attack.
Related terms
- Corrosion Fatigue
- Fatigue crack initiation and growth accelerated by a corrosive environment. Unlike SCC, it does not require a specific environment-material combination and can...
- Galvanic Corrosion
- Electrochemical attack that accelerates the dissolution of the more active (anodic) metal when two dissimilar metals are electrically coupled in an electrolyte.
- Pitting Corrosion
- Localised attack producing narrow, deep craters where the passive film breaks down. Pitting is self-propagating once initiated because the pit interior becomes...
- Selective-Phase Corrosion
- Attack that preferentially dissolves one phase or element from a multi-phase alloy, leaving the other phase intact but structurally weakened. Dezincification of...
- Stress-Corrosion Cracking (SCC)
- A failure mode combining sustained tensile stress with a specific corrosive environment, producing branching, often intergranular cracks that grow at stress intensities...