EVALUATION OF AHT AS CORROSION-INHIBITOR FOR ALPHA-BRASS IN ACID CHLORIDE SOLUTIONS

The corrosion inhibition of alpha-brass (Cu/Zn:67/33) in acid chloride solutions by 3-amino-5-heptyl-1,2,4-triazole (AHT) was evaluated by weight-loss, polarization, and capacitance measurements. The percentage inhibition was found to increase with increase of AHT concentration and the maximum value was 96% at [AHT] = 10 mM. The inhibition is attributed to the formation of a barrier layer of AHT(Cu,C1) + Cu2O. The presence of such a layer affects the anodic and cathodic polarization curves, the electrode capacitance, and the corrosion potential. The results show that AHT acts preferentially as an anodic inhibitor. Long-time tests show that the percentage inhibition does not change noticeably with time in either stirred or stagnant solutions, being higher in stagnant solutions.