Ohm’s Law in Corrosion

Definition

The corrosion cell obeys Ohm’s Law, with corrosion current equal to voltage divided by resistance. The rate of metal loss is directly proportional to the corrosion current flowing from anode to cathode.

Higher voltage drives higher current while higher resistance reduces it, so corrosion control works by lowering voltage or raising resistance. Voltage rises with strong oxidizers, oxygen gradients, and galvanic couples; resistance rises with passivation, protective films, and coatings. When a passive film fails, resistance drops and voltage rises together, so current density increases and damage localizes.

Related concepts

Corrosion Cell · Supercharging the Corrosion Cell · Voltage as Electromotive Force

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Part of The Blueprint of Water · ⚡ electrochemistry