Corrosion inhibition synergies on a model Al-Cu-Mg sample studied by localized scanning electrochemical techniques

Single and binary mixtures of corrosion inhibitors were studied by localized scanning electrochemical techniques on a model Al-Cu-Mg sample simulating the S-phase in AA2024-T3 in the presence of NaCl. Synergistic inhibition effects were observed for the mixtures of salicylaldoxime + Ce(III), salicylaldoxime + 8-hydroxyquinoline and the highest synergy was revealed for the mixture of 2,5-dimercapto-1,3,4-thiadiazolate + 8-hydroxyquinoline. The measurements detailed the anodic and cathodic activity over each metal composing the sample. A fiber-optic micro-optode was used for oxygen concentration monitoring and revealed depletion of oxygen. The combination of different techniques provided new highlights to understand the corrosion inhibition roles of single/mixed inhibitors on the simulated S-phase.