Supercharging the Corrosion Cell

Definition

Supercharging is the self-reinforcing intensification of corrosion when a failed passive film lowers resistance and raises voltage at the same time. Current density increases, metal loss accelerates, and damage localizes.

Resistance drops because the protective barrier is gone, and voltage increases because exposed bare metal has a much lower reduction potential than the surrounding passivated surface. The anode environment then diverges from the bulk water as acidity rises, chloride concentrates, and oxygen stays more available outside the pit than inside, strengthening the oxygen differential. Repassivation becomes unlikely and a surface disturbance becomes a feedback loop, which is the electrochemical basis of pitting.

Related concepts

Oxygen Differential Corrosion · Pitting Corrosion · Current Density

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Part of The Blueprint of Water · ⚡ electrochemistry