Embedded Reference Electrode for Potential-Monitoring of Cathodic Protective Systems

作者：Merten Bobbi E^*; Battocchi Dante; Tallman Dennis E; Bierwagen Gordon P

来源：Journal of the Electrochemical Society, 2010, 157(7): C244-C247.

DOI：10.1149/1.3421793

• corrosion protective coatings
• electric potential
• electrochemical electrodes
• iron compounds
• silver compounds
• substrates

Ag/AgCl reference electrodes were prepared in 0.03 M FeCl(3) solution using micrometer-scale silver (Ag) wires and embedded between the topcoat and metal-rich primer of a sacrificial coating system. The arrangement allows in situ measurement of the open-circuit potential (OCP), an indicator of the level of protection afforded by the coating to the substrate, via the embedded reference electrode (ERE) and aims to eliminate the standard, less-accurate practice of scheduled maintenance. This methodology allows the possibility of upgrading the monitoring and control systems presently used for impressed cathodic protection in addition to permitting the in situ observation of the corrosion protection levels for metal-rich sacrificial coatings. Measurements of the metal-rich primer/substrate OCP vs the ERE and vs a saturated calomel electrode (SCE) as a function of exposure time were the key experimental techniques to validate the use of an embedded electrode. Potentiodynamic experiments were executed to polarize the system using an SCE and second potentiostat. The impressed potentials were successfully monitored concurrently via the ERE and original potentiostat. Strengthened by the in situ OCP measurements with B117 salt spray chamber, this study shows the feasibility of the Ag/AgCl ERE for use in cathodic protective systems by effectively relaying OCP information.

• 出版日期2010