Corrosion product concentration in a single three-dimensional pit and the associated pitting dynamics

A single three-dimensional pit was generated on one electrode at different polarization potentials, and its inner corrosion product concentration was evaluated by inductively coupled plasma emission spectrometry (ICP-OES) and three-dimensional microscope. The openness of pit increased with increasing pit volume and rising potential. The pit inner corrosion product concentration decreased with increasing pit volume and rising potential. Higher potentials resulted in a bigger pitting current density. Pit formed at higher potentials showed a lower pit inner corrosion product concentration and a faster growing rate, indicating that pit growth rate was mainly determined by applied potential rather than mass transfer process.