The polarization decay of coated and bare steel specimens in saltwater was measured. A simple nested equivalent circuit with two "RC" constants was used to analyze the data. The values of the two "RC" constants were calculated for 2%, 20%, and 100% bare steel. A coated and scratched specimen with the bare area less than 1% was also analyzed with this procedure. It was observed that corroded steel specimens decay slower than the coated specimens. The decay rate decreased with the increase in bare area of coated steel. The pseudocapacitance values calculated from the time constants increased as the corroded bare area of coated steel was increased.

Subject
Circuits, Steel structures, Coated steel, Steel surfaces, Corrosion rate, Impedance, Corrosion products, Capacitance, Constants, Steel, Rust, Polarization decay, Electrode potential
Keywords:
polarization, polarization decay, equivalent circuit, condition assessment, non-destructive testing, coated steel
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1995
Association for Materials Protection and Performance (AMPP)
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