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Electrochemical impedance spectroscopy as a tool to measure cathodic disbondment on coated steel surfaces: capabilities and limitations
journal contribution
posted on 2015-11-01, 00:00 authored by Fari Mahdavi, Mike Yongjun TanMike Yongjun Tan, Maria ForsythMaria ForsythThe disbondment of protective organic coatings under excessive cathodic protection potentials is a widely reported coating failure mechanism. Traditional methods of evaluating cathodic disbondment are based on ex situ visual inspection of coated metal surfaces after being exposed to standard cathodic disbondment testing conditions for a long period of time. Although electrochemical impedance spectroscopy (EIS) has been employed as an effective means of evaluating various anti-corrosion properties of organic coatings; its application for assessing the cathodic disbondment resistance of coatings has not been sufficiently exploited. This paper reports an experimental study aimed at developing EIS into a tool for in situ measurement and monitoring of cathodic disbondment of coatings. A clear correlation between EIS parameters and the disbonded coating areas has been confirmed upon short term exposure of epoxy-coated steel electrodes to cathodic disbondment conditions; however the degree of this correlation was found to decrease with the extension of exposure duration. This observation suggests that EIS loses its sensitivity with the propagation of coating disbondment, and that in order to achieve quantitative determination of the coating cathodic disbondment localized EIS measurements are required to measure the parameters related to local disbonded areas.
History
Journal
Progress in organic coatingsVolume
88Pagination
23 - 31Publisher
ElsevierLocation
Amsterdam, The NetherlandsPublisher DOI
ISSN
0300-9440Language
engPublication classification
C Journal article; C1 Refereed article in a scholarly journalCopyright notice
2015, ElsevierUsage metrics
Keywords
Science & TechnologyPhysical SciencesTechnologyChemistry, AppliedMaterials Science, Coatings & FilmsChemistryMaterials ScienceOrganic coatingCathodic protectionCathodic disbondmentElectrochemical impedance spectroscopy (EIS)ORGANIC COATINGSMILD-STEELDELAMINATIONDEGRADATIONPROTECTIONCORROSIONMETALSMECHANISMADHESIONEISMechanical Engineering
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