The Corrosion Coulometer—A New Corrosion Monitor for Steel Structures

A new type of corrosion monitor (corrosion coulometer) has been developed for use on steel structures. It is designed to incorporate corrosion products and airborne contaminants into the system in order to simulate actual conditions in local microclimates within or in the vicinity of a structure. It operates as a galvanic cell when wet and uses a microcoulometer to store the electrical output, although instantaneous voltages and/or currents may also be monitored. Evaluation in the laboratory by monitoring successive wet/dry cycles and exposure on the roof of a building at Lehigh University for 20 weeks showed excellent correlations with corrosion of adjacent steel panels. It was estimated that the cell should have a lifetime of at least four years.