Research and comparative analysis of corrosion resistance of copper-zinc alloys in chlorine-containing environments

This work presents the results of studies of the electrode potential of α, β and α+β brasses, determined corrosion currents in chlorine-containing environments, and conducted tests on their dezincification in a copper chloride solution. In order to more deeply study the properties of brass, corrosion currents and electrode potential in chlorine-containing environments were determined for pure metals: copper and zinc. In the course of the work, graphs were constructed of the potential of copper, zinc, α, β and α+β brasses versus the etching time in sodium chloride solutions and a sodium chloride solution with the addition of ammonium chloride. Corrosion currents were determined in a sodium chloride solution: for copper (38 μA), α brass (70 μA), α+β brass (113 μA), β brass (88 μA) and in a sodium chloride solution with the addition of ammonium chloride: for copper ( 14 µA), zinc (71 µA), α brass (37 µA), α+β brass (44 µA), β brass (42 µA). Based on the results of a study of the resistance of alloys to dezincification, the following data were obtained: dezincification depth of brass α - 450-500 µm, α+β - 950-1000 µm, β - 600-700 µm. The results of studies of corrosion currents in chlorine-containing environments correlate with the results of dezincification experiments. The studies carried out confirm the assumption that in double brasses the α and β phases form a corrosion element due to the difference in chemical composition, and, consequently, different electrode potentials, which leads to the loss of zinc to a slightly greater extent than in β brass.