Acceleration and quantitative evaluation of degradation for corrosion protective coatings on buried pipeline: Part I. Development of electrochemical test methods

• Published in: Progress in organic coatings Vol. 76; no. 4; pp. 778 - 783
• Main Authors: Lee, S.H., Oh, W.K., Kim, J.G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2013
• Subjects: Coating degradation; Electrochemical impedance spectroscopy; Metal dissolution; Organic coating; Oxygen reduction; Pulsed potentiostatic polarization; Pulsed potentiostatic polarization; Oxygen reduction; Metal dissolution; Coating degradation; Organic coating; Electrochemical impedance spectroscopy
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2012.06.010

► Cathodic disbondment and oxide lifting are attributed to the coating delamination. ► Coating delamination is accelerated effectively by the pulsed potentiostatic test. ► The Rct of the coated system is closely related to the delamination area. The electrochemical degradation of polyethylene coated onto SS400 was examined in synthetic groundwater. Electrochemical techniques (electrochemical impedance spectroscopy, potentiodynamic and potentiostatic polarization tests) and surface analysis (scanning electron microscopy) were used to accelerate and evaluate the coating degradation. The pulsed potentiostatic polarization test accelerating both the cathodic reduction and anodic oxidation reactions was applied to reproduce the coating degradation mechanisms of cathodic disbondment and oxide lifting. The applied potentials were determined to be ±300mVSCE versus open-circuit potential from the analysis of the anodic and cathodic polarization data. Results from the EIS confirmed that coating degradation is accelerated effectively by the pulsed potentiostatic polarization testing.