Real-time corrosion monitoring for carbon steel materials in soil was conducted utilizing coupled multielectrode sensors. It was demonstrated that the coupled multielectrode sensor is an effective realtime tool for monitoring the corrosion rate in soil. The steady state corrosion rate measured in watersaturated soil was found to be approximately 2 to15 µm/year. However, the corrosion rate in a space filled with water was several orders of magnitude higher than those found in the densely packed soil saturated with water. The coupled multielectrode sensor also provided real-time indications for the effectiveness of cathodic protection in soil.
Corrosion of metallic components in soil has been a concern in many fields, including the pipeline industry and nuclear waste disposal programs. Metal loss corrosion probes based on electrical resistance methods have been used as online tools for corrosion monitoring in soil1-4. However, these probes are not sensitive enough for localized corrosions, such as pitting or crevice corrosion5. Coupled multielectrode sensors have been recently used as in situ or online monitors for localized corrosions in laboratories and industry applications6-13. Some of the examples include quantitative and real-time corrosion monitoring for cathodically protected systems11and coated metal components12. The coupled multielectrode probes were also used as a real-time corrosion monitor for the corrosion of carbon steel rebar material in concrete13. In the present work, coupled multielectrode corrosion probes were used to online measure the corrosion rate of carbon steel material in soil. The experimental results of corrosion rates under different conditions, including cathodic protection conditions, are presented in this paper.
