Computational Modeling of the Stability of Crevice Corrosion of Wetted SS316L

The stability of localized corrosion sites on SS 316L exposed to atmospheric conditions was studied computationally by considering the wetted cathode and the crevice anode separately and linking them via a constant potential boundary condition at the mouth of the crevice. The limitations on the ability of the cathode that are inherent due to the restricted geometry were assessed in terms of the dependence on physical and electrochemical parameters (temperature, electrolyte layer thickness, solution conductivity, and the size of the cathode). An analysis of variance showed that the solution conductivity and the length of the cathode were the most important parameters in determining the total cathodic current capacity of the external surface. A semi-analytical equation was derived for the total current from a restricted geometry held at a constant potential at one end.