Organic coatings are widely used in the steel structures of power transmission and distribution systems to protect against corrosion. Early and accurate detection of coating degradation is clearly of critical importance. We investigated two methods for evaluating coating degradation—the alternating current (AC) impedance method and the current-interrupt (Cl) method—by exposing coated steel specimens to either long-term atmospheric exposure or shorter-term salt-water immersion, and then measuring their electrochemical behavior. We also analyzed coating degradation by x-ray probe microanalysis.

Subject
Circuits, Films, Coatings, Substrates, Impedance, Capacitance, Coating degradation, Impedance measurements, Metals, Film thickness, Carbon steel, Immersion, Paints
Keywords:
Coating, Corrosion, Electrochemical techniques, Alternating current impedance, Current interrupt method, Under-film corrosion
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2011
Association for Materials Protection and Performance (AMPP)
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