Modeling of current paths in advanced electrochemical sensors for improving corrosion data interpretation

Proton conductive membrane-based sensors allow for electrochemical measurements in low-water content environments. However, electrode placement on the membrane promotes unconventional current pathways. As such, electrode and membrane geometries can impact electrochemical analysis of corrosion and conductivity measurements. In conventional sensors, the current carried by ions in the conducting media is able to travel in a 1-dimensional path between the electrode surfaces, and so the current path between these electrodes are uniform. However, advanced sensors with membranes laid atop the electrode surfaces require a 2 or 3-dimensional analysis. The current path is first normal to, then parallel to the current-collecting electrode's surface. In this case, the intensity of this current can vary strongly across the surface of the electrode, which means a correction is required when incorporating the effective contact area of the electrode during analysis. In this paper, we utilize finite element analysis to model the current pathway and intensity for membrane-based corrosion sensors. Results provide correction factors incorporated into data analysis approaches that improve the use of planar, membrane-based corrosion sensors for monitoring natural gas transportation pipelines.