Effects of the IR Drop on the Electrochemical Corrosion of X80 Pipeline Steel in Different Solutions

Abstract

Polarization curves are popularly used in many investigations; however, some wrong results are obtained when inexperienced researchers do not deeply understand electrochemical processes. In this study, the effects of the IR drop (Deviation due to I (current) and R (resistance)) and scanning direction on polarization curves were investigated. Three different test methods were used to test the polarization curve of X80 pipeline steel in five kinds of solutions. The different scanning directions led to differences in the cathodic polarization curves. In addition, the effect of IR drop on the Tafel curve in acidic solutions is significantly greater than in neutral and alkaline solutions. There is a large effect of the IR drop on shapes and fitting results of polarization curves in acidic solutions, and the IR drop must be considered for the fitting of curves. Scanning direction has an influence on the shape of polarization curves when a layer of corrosion products is formed on the steel surface, and a novel two-electrode coupon was introduced to solve this problem.