Evaluating the Corrosion Behaviors of Pipe Component Materials Used in Commercial Refrigeration Systems

摘要

When the piping component materials used in refrigeration systems corrode, this degradation is often due to the materialsu27 environment (or, more generally, the presence or lack of a corrosion supporting electrolyte), galvanic coupling between mismatched materials, the substances carried by the piping system, and/or the temperature of the substances surrounding the components. Laboratory testing was performed in collaboration with a local industry partner to qualify and quantify the electrochemical ­ and, in this case, corrosion behaviors of steel and aluminum alloys often used in such piping systems as those behaviors change with different material coatings. A combination of Electrochemical Impedance Spectroscopy (EIS) and Open Circuit Potential (OCP) data provided the means to characterize the thermodynamic tendencies and kinetic behaviors of corrosion activity through these coatings, allowing us to draw conclusions about which material treatments (coatings) are most appropriate for reducing corrosion in refrigeration pipelines. While most coatings proved to inhibit surface corrosion on the alloys when compared to bare samples, we found that electrochemical testing can be used to provide a relative performance ranking among coated samples, with the best corrosion protection attributed to a combination of coating chemistry, coating thickness, and surface adhesion.