Electrochemical noise (EN), linear polarization resistance (LPR), and harmonic distortion analysis (HDA) were used with three-electrode probes to monitor the corrosion occurring in soil near a gas pipeline under cathodic protection. The test site was a cathodic protection (CP) test station where impressed current CP was applied to a 2 in. (5.1 cm) diameter coated steel pipe using an 84 in. (0.2 m) TA-2 high-silicon cast iron anode. Electrochemical measurements were made at two locations inside the CP field and one outside the CP field. One set of measurements was made with the CP system off to obtain base line data and two with the CP system on. Results indicate that CP does not interfere with the measurement of corrosion rate and pitting factor using EN, LPR, and HDA techniques.

Subject
Depolarization, CP coupons, Piping, Corrosion rate, Pipelines, Corrosion probes, Corrosion protection, Impressed current, Corrosion coupons, Polarized potential, Linear polarization resistance, Electrodes, Soil
Keywords:
corrosion, natural gas, corrosion probe, electrochemical noise, harmonic distortion, linear polarization resistance, gas transmission pipeline, soil, soil resistivity
Government work published by the Association for Materials Protection and Performance (AMPP) with permission of the author(s). Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2004
GOV
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