A novel physical criterion for modeling repassivation based on an extended point defect model

The ability of metals to re-form passive films is crucial for ensuring the longevity and reliability of critical components in demanding environments. Building on an extended Point Defect Model (PDM) considering chloride ion induced passive film breakdown, we introduce a physical criterion to model the dynamics of self-healing from a depassivated state. The stainless steel AISI 316 L was selected due to its practical relevance and the availability of published data demonstrating the dependence of repassivation on environmental factors. Cyclic voltammetry (CV) sweeps under varying chloride ion concentrations, temperatures, pH values and scan rates were simulated using the enhanced extended PDM. The predicted shifts in key electrochemical system responses, such as corrosion current, open circuit potential, induction time, critical breakdown potential and the repassivation potential, align well with literature findings. Furthermore, the model predicts passive film breakdown at low potentials, a phenomenon consistent with both experimental observations and fundamental thermodynamics. The capability to forecast passive film breakdown and repassivation facilitates optimal material selection and thus enhances component operation under transient environmental loads.