Pitting Potential

Definition - What does Pitting Potential mean?

Pitting potential refers to the least positive current and voltage at which pits develop or grow on a metallic surface. This is the electrochemical potential in a given environment above which a corrosion pit initiates on a metallic surface. Knowing the pitting potential is important because pits form and propagate at and above the critical pitting potential.

Corrosionpedia explains Pitting Potential

Pitting for a given material is characterized electrochemically by the critical pitting potential (Epit). Epit lies between the noblest potential, where no grown pit is found, and the least noble potential, where pitting occurs. Epit is the most negative potential above which pits nucleate and grow, which approximates the noblest potential below which a pit never forms.

Pitting potentials are usually determined from steady-state anodic polarization curves. The most reliable approach is to use a potentiostatic technique in which a constant potential is applied, and the current is recorded as a function of time. These potentials are often presented in a potential-pH graphical diagram.

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