AN EXPERIMENTAL STUDY INVESTIGATING THE CORROSION BEHAVIOR OF CU-NI ALLOYS IN WATERS TREATED AND UNTREATED WITH ANTI-CORROSIVES

This paper discusses an experimental study on how water quality affects the corrosion rate of Cu-Ni Alloys, such as those used within a heat exchanger system. Various types of water suitable for the heat exchanger operation have been tested to predict the duration during which corrosion would become a risk. Since corrosion is governed by electrochemistry, an electrochemical experimental setup was designed, consisting of a three-electrode electrochemical cell designed to simulate the on-site state and conditions of a 90-10 Cu-Ni tube bundle inside the heat exchanger. The working electrode in use is a 90-10 Cu-Ni Rotating Cylinder Electrode (RCE). The electrolyte solution was varied with different pH values, temperature and compositions. The corrosion rate was measured by use of the Tafel method. Experiments were performed with two solutions; De-Ionized water and Tap water. Further experimentation with anti-corrosives was also performed. All measurements were produced using a G300 Gamry (R) Potentiostat (computer controlled) conjugated with two general purpose electrochemical softwares: Gamry Framework (R) and Gamry Echem Analyst (R). Trends of the corrosion rate as a function of pH and temperature were analyzed. Field Emission Scanning Electron Microscope (FE-SEM) tests have also been performed to determine the products, methods and elemental effects of the corrosion. Results and discussions are provided with pertinent conclusions.