The corrosion of Cu-30Ni in presence of 3-amino-1,2,4-triazole (ATA) was examined in 3% NaCl solution containing ammoniac. For the cathodic processes, the addition of ATA slows down markedly the reduction reaction of dissolved oxygen, and the cathodic process is controlled merely by the hydrogen evolution. Besides, ATA inhibits efficiently the hydrogen evolution itself when the kinetics parameters were evaluated from a non-linear regression calculation according to Levich-Koutecky relationship. For the anodic processes, the addition of ATA suppressed completely the current peak observed at the active-passive transition revealed in its absence, and the passive current plateau is observed directly from the corrosion potential. Therefore, the addition of ATA reduces both the anodic and the cathodic partial currents of the corrosion process. The inhibiting efficiency of ATA is high, more than 98%, and even enhanced in presence of ammoniac. It was found also that this inhibiting effect increased with the immersion period. (C) 2004 Elsevier Ltd. All rights reserved.