Electrochemical Impedance Spectroscopy: Characterizing the Performance of Corrosion Protective Pipeline Coatings

Electrochemical Impedance Spectroscopy, EIS, measures how the frequency dependent electrical impedance of a coating film changes during its exposure to corrosive media. The technique is fairly rapid, often non-destructive and is sensitive to changes in the coating and can also be performed in the field. The electrical properties of the paint film are measured through its thickness between the metal and an exterior electrode which is usually a reservoir of a conductive salt solution on the outer surface. Polymer pipeline coatings and linings are designed to be barriers to water and dissolved salts that would otherwise corrode the steel water pipes. High values of impedance are characteristic of coatings without defects and that do not absorb water or salts. Diminished values of impedance show that either a defect has formed or that the coating has absorbed electrolyte that may eventually corrode the metal pipe substrate. The technique was used to compare the performance of modern epoxy or polyurethane coatings with coat tar enamel that is known to have a much extended service life, if undisturbed. Results show that, after one and a half years, all the coatings are performing well although the polyurethane coatings are performing better than the epoxies.

Language

  • English

Media Info

  • Media Type: Web
  • Features: References;
  • Pagination: pp 1521-1532
  • Monograph Title: Pipelines 2015: Recent Advances in Underground Pipeline Engineering and Construction

Subject/Index Terms

Filing Info

  • Accession Number: 01576619
  • Record Type: Publication
  • ISBN: 9780784479360
  • Files: TRIS, ASCE
  • Created Date: Aug 18 2015 3:05PM