Investigating metal-inhibitor interaction with EQCM and SVET: 3-amino-1,2,4-triazole on Au, Cu and Au–Cu galvanic coupling

This study reports amultiscale electrochemical investigation of the interaction between the organic compound 3-amino-1,2,4-triazole (ATA), regarded as corrosion inhibitor, and two noblemetals (Cu andAu), either separated or under galvanical coupling. Open circuit potentialmeasurements showthatCuis not protected by the application ofATA, having its potential shifted towardsmore negative values, while on Au exhibits a slight inhibitive effect. The adsorption free energies were determined using the electrochemical quartz crystal microbalance (EQCM), with values that correspond to physisorption on eithermetal. The surface reactivity of the inhibitor-modifiedmetals in chloride-containing aqueous solution was studied using the scanning vibrating electrode technique (SVET), showing high spontaneous activity, associated to electron transfer reactions in systems containing Cu and 3-amino-1,2,4-triazole.