Passive alloys, crevice corrosion deaeration

The first point to emphasize is that crevice corrosion of passive alloys does not occur in environments deprived of oxidizing species other than water. Generally, it does not occtrr in deaerated solutions. On the contrary, oxidizing agents such as many biocides (hypochlorite, chlorine, chlorine dioxide, etc.) may catrse crevice corrosion. 

Conversely, there is some agreement that a critical value (usually referred to as protection potential) exists that is the maximum possible value of below which no crevice corrosion may propagate significantly. This is consistent with the fact that crevice corrosion of passive alloys in chloride environments does not occur in deaerated environments. 

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