Benzotriazole and cerium chloride as corrosion inhibitors for AA2024-T3: An EIS investigation supported by SVET and ToF-SIMS analysis

Highlights: • EIS shows that the BTA film increases the passive layer impedance of AA2024. • SVET indicates that Cu ions are necessary in order to obtain a protective CuBTA layer. • SVET depicts a corrosion increase induced by CeCl₃ at the beginning of immersion. • EIS suggests a positive synergy between BTA and CeCl₃ up to 2 weeks of immersion. • ToF-SIMS analysis detected hybrid BTA/cerium films on AA2024 and on the Cu electrode. - Abstract: The inhibitive effects provided by benzotriazole (BTA) and cerium chloride (CeCl₃) on 2024-T3 aluminium alloy were assessed, individually and combined, in 0.05 M NaCl electrolytes, by means of Electrochemical Impedance Spectroscopy (EIS). From the analysis of impedance fitted parameters, a synergistic effect appears to exist between both inhibitors until 14 days of immersion. The Scanning Vibrating Electrode Technique (SVET) was applied to an Al/Cu galvanic coupling model in order to better comprehend the observed inhibitive actions. Additionally, Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) was employed to evaluate the in-depth distribution of species related to the inhibitive film/alloy interface.