Intergranular corrosion of copper in the presence of benzotriazole

While benzotriazole (BTAH, C 6H 5N 3) has long been known as an efficient inhibitor for the general corrosion of copper, this paper documents the occurrence of intergranular corrosion (IGC) of copper in a salt solution (3.5 wt.% NaCl) in the presence of 1 mM BTAH. This occurs above a breakdown potential, E b, at the end of the passive region. Higher concentrations of BTAH broaden the passive region and shift E b to more noble values. Pitting is the mode of corrosion above E b in the presence of a higher concentration of BTAH, while IGC occurs above E b in the presence of 1 mM of BTAH.