Probing top-of-the-line corrosion using coupled multi-electrode array in conjunction with local electrochemical measurement

An experimental method has been developed for probing top-of-the-line corrosion (TLC) of pipeline steel based on the use of the wire beam electrode (WBE) in conjunction with local electrochemical measurements. Results show that the location of the droplet, the droplet retention time, the water condensation rate and the local TLC rate could be well determined through the macro-cell current mapping and local electrochemical measurements. The precipitation and the scaling tendency of the FeCO3 beneath the droplet were quantitatively estimated. The micro-cell corrosion was significantly influenced by the thickness of the condensed water film and the protectiveness of the FeCO3 layer. The discrepancy of the film formation inside and outside the droplets was the driving force of macro-cell corrosion. The in-situ measurement and visualization of the corrosion processes and kinetics using the modified WBE could be conveniently used to facilitate the understanding of the initiation and propagation of localized TLC.