INHIBITING EFFECTS OF BENZOTRIAZOLE ON THE CORROSION OF ALPHA-AL-BRONZE IN SALINE WATER

The inhibiting effect of benzotriazole (BTA) on the corrosion of alpha -Al-bronze (Cu-7% Al) in 3.4% NaCl was studied. BTA showed good inhibi tion effects from short up to extended periods of time (about six week s). The morphologies of the alloy surface were monitored after various periods of corrosion in the absence and presence of BTA, using SEM. T he corrosion products were identified by X-ray diffraction. Corrosive attack occurs very early in the absence of BTA, leading to general and pitting corrosion. BTA was found to have a stronger inhibiting effect on the anodic dissolution of copper than on the cathodic reduction of oxygen. The current-potential relation is divided into two regions: r egion I within which BTA has a strong effect on the charge transfer ki netics, and a limiting current region where BTA has no significant inh ibiting effect. It is also shown that the interaction of BTA with a Cu 2O-covered alloy surface is faster than on reduced alloy surfaces, alt hough the protection efficiency on the latter is slightly better than on the former.