Repassivation behaviour of stressed aluminium electrodes in aqueous chloride solutions

The combined influence of mechanical stress and chemical environment on the pitting susceptibility of aluminium electrodes was studied by integrating open circuit potential measurements and electrochemical repassivation modelling. The transient degradation of aluminium oxide owing to a tensile stress field and its subsequent repassivation are observed as an abrupt negative potential excursion followed by a slow decay of the corrosion potential back towards its initial value prior to the mechanical loading. Experiments were performed and an electrochemical repassivation model was established to quantitatively describe the dependence of oxide dissolution rate and the reciprocal of cathodic Tafel slope on chloride concentration.

► We studied the combined influence of stress and chloride on aluminium electrodes. ► We performed both experiments and electrochemical repassivation modelling. ► Model takes oxide growth, dissolution and cathodic reactions into consideration. ► Repassivation kinetics show strong dependence on chloride concentration.