Contribution to the synergistic effect of triazole derivatives on corrosion inhibition of Cu-30Ni alloy in aerated NaCl 3% in presence of ammonia

摘要

The electrochemical behavior of Cu-30Ni alloy was investigated in aerated NaCl 3% in presence of ammonia solutions containing 3-amino-1,2,4-triazole (ATA) and 3-4'-bitriazole-1,2,4 (BiTA), separately and mixed. For the ca-thodic processes, the addition of ATA, BiTAand mixture slows down markedly the reduction reaction of dissolved oxygen, and the cathodic process is controlled merely by the hydrogen evolution. For the anodic processes, the addition of ATA, BiTA and mixture suppressed completely the current peak observed at the active—passive transition revealed in their absence, and the passive current plateau is observed directly from the corrosion potential. Therefore, the addition of ATA, BiTAand mixture reduces both the anodic and the cathodic partial currents of the corrosion process. The inhibiting efficiency of mixture 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.