Pitting Corrosion of Some α‐Brasses in Neutral and Alkaline Solutions Containing Halide Ions

Abstract

The pitting corrosion behaviour of some a-brasses (Cu%: 85, 70, 67,63 and 60) in neutral and alkaline solutions containing various halide ions was studied. The pitting corrosion resulted in dezincification in all cases and the pitting potential was found with few exceptions to increase in the order: Cu 60 < Cu 67, Cu 70 < Cu 63 < Cu 85 < Cu 100. Increase of pH was found to shift the pitting potential to more positive values and at highly enough pH values the pitting corrosion was inhibited in some cases. The instantaneous current, at constant potential and in absence of pitting, was found to varies linearly with (lltime)lR. at time 3 2 0 seconds. During the initial stages of pitting, the current was found to fit Engell-Stolica equation.The steady corrosion potentials in presence of Br-and I-ions were found to be nearly coincident with those of Cu/Cu halide couples while they were far from the theoretical values in presence of C1-ions and they changed negligibly in presence of F-ions.