Effect of Specific Water Quality Parameters on Copper Corrosion

The objective of this study is to clearly understand the effect of specific water quality parameters like pH, dissolved oxygen (DO), conductivity, and buffering capacity (attributable to dissolved inorganic carbon [DIC] species) on copper corrosion. These parameters were studied by carrying out bench scale studies in a batch reactor. In the absence of any active chemical species and oxidants except O2 and H+, the corrosion rate and passivation of the copper surface was strongly dependent on the DO at a given pH. Pertinent aqueous-phase chemical speciation, which was calculated by Mineql+ software, was used to explain the experimental results. The effect of chloride (Cl–) and DIC on the initial and short-term corrosion rates was also investigated. Potentiodynamic polarization scans were used not only to determine corrosion rates but also to study the passivation of the copper surface as a function of DIC and Cl– concentrations at different pH values. The mode of corrosion inhibition (i.e., anodic, cathodic, or mixed) with changes in the aqueous-phase chemical speciation was also investigated using electrochemical techniques.