PITTING CORROSION OF POLYCRYSTALLINE ANNEALED COPPER IN ALKALINE SODIUM-PERCHLORATE SOLUTIONS CONTAINING BENZOTRIAZOLE

The pitting corrosion of copper in alkaline solutions in the presence of benzotriazole (BTA) was investigated. The presence of BTA shifts the breakdown (E(b)) and the repassivating (E(p)) potentials positively with respect to the blanks. However, the shift of E(p) becomes smaller than that of E(b), particularly at pH 9 and 11. Pitting corrosion involves the formation of crystallographic pits. The kinetics of the process fits a nucleation and growth mechanism involving instantaneous nucleation and 3D growth under charge transfer control. The spatial distribution of pits indicates that there is no marked influence of a pit on the nucleation and growth of other pits.