What Does Chloride Ion Content Mean?
Chloride ion content is the concentration or amount of chloride ions in a solution.
Studies regarding iron corrosion in sulfuric acid media with a pH near 3.0 have found
that the concentration of ions can either accelerate or decelerate the rate
of corrosion. Chloride ions accelerate corrosion considerably when the anodic
reaction contributes significantly to the overall kinetics.
Corrosionpedia Explains Chloride Ion Content
Chloride ions decrease the protective action of so-called anodic inhibitors (K2Cr2O7 and NH2CH2CH2OH) whereas sulfate ions interfere with the action of thiourea, a cathodic inhibitor. The corrosion potential is independent of the chloride concentration but is shifted in the negative direction by sulfate. These observations are interpreted in terms of the properties of FeCl-- and FeSO4-- complexes. The chloride complex serves simply to carry Fe++ away from the metal surface.
When alloys are put into an acidic solution having a high choride ion concentration level, the acidic nature as well as pH value of the solution increases. This also increases the corrosion rate.