Contribution to the study of brass dezincification

Abstract

It is possible to detect microscopically dezincification in artificial sea water at 50°C of hard or recrystallized 63/37 two phase (α + β) and single phase (α) brass samples, after simple immersion or after exposure in differential aeration cells. The minimum times to be able to detect the phenomenon are 2h and 1h respectively. This dezincification goes faster in α + β than in a single phase α-phase, and the process occurs more rapidly in differential aeration cells than by simple immersion. The aspect of dezincified zones is different for single phase α-brass, as compared to α + β brass. In the latter, dezincified zones tend to replace the β-phase of the structure and are thus very much confined to grain boundaries. Samples which do not present β-phase show dezincification spreading out over entire grains. Furthermore, metallographic observations point to a cathodic dezincification process in a brass-sea water-copper oxichloride brass cell, in which the oxichloride would polarize the