Monitoring corrosion rates with ER-probes–a critical assessment based on experiments and numerical modelling

Abstract

Electrical resistance (ER) probes are a technique used to monitor the corrosion rate (CR) of metals in a wide range of applications and industries. However, limited data comparing CR measured with ER-probes, weight loss and electrochemical methods is available. The aim of this work is to provide data regarding the reliability of CR measurements with ER-probes by comparison with LPR, EIS and weight loss measurements and to provide suggestions for designing ER-probes depending on the expected corrosion mechanism and CR. To evaluate the ER-probes reliability in CR measurements, both uniform and localised corrosion in four different environments were studied. CRs obtained with ER-probes showed good agreement with weight loss and electrochemical measurements. Numerical models were used to optimise ER-probe geometry regarding the expected corrosion type and CR, and to study the effect of Joule heating. Design charts were proposed to support ER-probes design concerning the expected CR in certain applications.