Galvanic Corrosion Inhibition: Validation of Simple Laboratory Testing

Pipeline cladding, pipeline lining, valves or other pipeline fittings can present the coupling of two or more different metals. This represents a risk of galvanic corrosion when an electrochemical cell is set-up, generating preferential corrosion of one metal over another. In a worst case scenario, this may lead to pipeline failure with associated environmental risks, shut down periods, loss in production and ultimately costs. Commercially available corrosion inhibitors have being applied for many years with success and there are numerous electrochemical techniques and test protocols to help select the “right” corrosion inhibitor for the particular application. The effectiveness of different corrosion inhibitors with specific metals has been studied and proven in the past, however the effect of corrosion inhibitors on galvanic couples can still be considered a new subject. This paper describes the laboratory work performed to test the inhibition of galvanic corrosion using different formulations and commercially available products. The results have shown simple electrochemical techniques and common equipment can be used to obtain meaningful and relevant data.  Although additional research can be performed on the subject, the results confirm that the selection of the right corrosion inhibitor is fundamental to the integrity of a galvanic couple.