Abstract
This study focuses on the application of electrochemical corrosion rate measurement and solid surface analysis approaches to understanding drinking water copper corrosion. Applying electrochemical approaches combined with copper solubility measurements, and solid surface analysis approaches are discussed. DC polarization (DCP) and Electrochemical Noise (ECN) measurements were carried out to obtain Stern-Geary constant and noise resistance, respectively. ECN has the advantage in that corrosion behavior can be monitored as a function of extended periods of time without the need to apply an artificial potential that can potentially alter the metal surface in an unnatural way. ECN allows for the prediction of how natural films on the corroding metal surface are impacted by changing water quality conditions. Specific film degradation and changes on copper metal were observed by Electrochemical Impedance Spectroscopy (EIS). Cyclic Potentiodynamic Polarization (CPP) measurements are applied to provide useful information about the properties of predicting pitting corrosion tendencies. These electrochemical methods, however, proved to be insufficient for understanding and predicting the buildup of corrosion products on copper surfaces. A study on the development of surface scales was carried out using X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). These approaches provided a better description of the mechanisms associated with the early build-up of corrosion products on the copper surface.
