Comparative Effects of Tolytriazole and Benzotriazole Against Sulfide Attack on Copper

Corrosion inhibition of copper by tolytriazole (TTAH) in comparison with benzotriazole (BTAH) was investigated in unpolluted and sulfide polluted 3.5 % NaCl. Both TTAH and BTAH give approximately similar results in unpolluted salt water. Electrochemical techniques illustrate that TTAH gives about (40%) higher efficiency than BTA in case of sulfide polluted media. Surface analysis by X-ray photoelectron spectroscopy reveals the presence of both sulfide and TTAH on the corroded surface. In sulfide polluted salt water TTAH shows better performance than BTAH. The mechanism of protection is attributed to the formation of protective film of TTAH or BTAH. The rate of destruction of the protective film in TTAH is lower than that of BTAH in the presence of sulfide ions. This result is established at sulfide concentration as low as 10-3 M in the presence of 10-2 M TTAH. The gained results prove that TTAH gives better resistance against sulfide attack.