Theory 152/Steel corrosion/Threshold lens
Pitting Needs a Chloride Threshold
The claim
Pitting corrosion begins above a threshold in the ratio of chloride to alkalinity at the steel surface, so a well-passivated steel tolerates more chloride.
01Mechanism
Chloride breaks the passive film locally; the ratio determines whether the film can repair itself.
02Prediction
Pitting should track the ratio.
03Refutation
Pitting tracking chloride alone would remove alkalinity.