Quantitative analysis of scanning electric current density and pH-value observations in corrosion studies

The corrosion behaviour of a well-investigated aluminium alloy AA2024-T3 in sodium chloride solution was observed via scanning vibrating and ion-selective electrode techniques. A completely new approach to the analysis of the obtained data is demonstrated. The 3D fitting procedures of current density distribution and of the local pH-values above the corroding surface allow precise quantification and localization of reactive centres. Global physical parameters such as the total anodic current and the proton production rate become accessible. Both increase simultaneously with immersion time, while their ratio remains constant