Protective coatings for structural steel bridges include galvanized steel. The zinc alloy layers of galvanized steel provide beneficial galvanic coupling with the steel substrate to mitigate corrosion activity. However, coating defects exposing the steel substrate to the chloride exposure environments can affect the zinc corrosion activity and thus the mitigation of steel corrosion. Electrochemical measurements including open-circuit potential, linear polarization resistance, and the electrochemical noise (EN) technique were conducted on coated steel plates with defects subjected to various chloride solutions to identify the zinc activity and steel corrosion. The EN testing was used to identify the local electrochemical activity of the zinc and the steel substrate and corrosion mitigation afforded by the coatings when subjected to a chloride solution.

Subject
Steel surfaces, Corrosion currents, Electrochemical noise, Steel coupons, Corrosion activity, Salt solutions, Chloride solutions, Galvanized steel, Steel, Coating defects, Zinc, Electrochemical potential, Electrode potential
Keywords:
Electrochemical Noise, Galvanized, Steel, Coatings, Corrosion
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2022
Association for Materials Protection and Performance (AMPP)
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