Module Six of CCE 281 Corrosion: Impact, Principles, and Practical Solutions

Crevice Corrosion

The chronology of a Crevice

Stage Two, Restricted Convection

Stage two of a crevice formation

Because of the difficult access caused by the crevice geometry, oxygen consumed by normal uniform corrosion is very soon depleted in the crevice. The corrosion reactions now specialize in the crevice (anodic) and on the open surface (cathodic). The large cathodic surface (Sc) vs. anodic surface (Sa) ratio (Sc/Sa) that forms in these conditions is a definitive aggravating factor of the anodic (corrosion) reaction.

Calculation example

This oversimplified example illustrates one aspect of a crevice situation. The next step in a crevice situation stabilizes it into a permanent problem that will need drastic corrective measures.

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