Seawater as an Electrolyte
Seawater as an Electrolyte.
Seawater is an excellent electrolyte. The presence of a large amount of
dissolved salts, sodium chloride (NaCl), that are ionized make it an excellent
conductor.
The chloride ions is particularly aggressive as it causes a breakdown of passivity causing pitting, crevice corrosion and stress corrosion cracking on most stainless steel grades.
The chloride ion is also particularly aggressive as most chloride compounds are highly soluble, which limits the formation of polarizing anodic films.
Seawater also usually contains enough dissolved oxygen for reducing water
to be the prevalent cathodic reaction in most cases. see also Galvanic Series Metals Seawater
Source : "Corrosion Control" NAVFAC
MO-307 September 1992
see also
Seawater Corrosion and Material Selection
Stainless Steel Corrosion Seawater
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