Comparing Electrochemical Impedance Spectroscopy Methods for Estimating the Degree of Delamination of Organic Coatings on Steel

Abstract

Electrochemical impedance spectroscopy (EIS) was used to evaluate the degree of delamination of the epoxy primer Uniprime ED-41 electrocoated on phosphate-treated cold-rolled steel in 3.5% NaC1 exposed to air. Specimens with coating thicknesses of 20.3 and 20.8 ~m and surface areas of 78.5 cm 2 were used. Coating parameters were obtained using a circuitanalog model. The area of delamination was estimated using several EIS parameters, including the pore resistance and the break point frequency. These values were compared to the corroded area determined visually. All methods considered exhibited a strong correlation over some or all of the range of exposure times.

Investigation of mechanical and corrosion properties of an Al–Zn–Mg–Cu alloy under various ageing conditions and interface analysis of η′ precipitate

“…According to the reports in ref. [27][28][29], the SCC susceptibility could be evaluated by a ratio r tf , which was calculated by:…”

Electrodeposition of r-GO/SiC nano-composites on Magnesium and its Corrosion Behavior in Aqueous Electrolyte

“…Delamination area is evaluated in order to specify the capacity of a coating to withstand in corrosion medium without peeling out from the substrate. Delamination area is calculated based on equation (7) [57] in which Specific polarization resistance,( )is associated with the charge transfer behavior of the metal substrate, and can be estimated using the linear polarization of an uncoated sample of the substrate. The polarization test is conducted in 0.1M NaCl electrolyte.…”

Non-Contact Acoustic Emission Monitoring of Corrosion under Marine Growth

“…However, the PDP is not considered a non-destructive technique and not fit for long-term monitoring [ 21 ]. Applications of less destructive (compared to PDP) techniques, such as Linear Polarization Resistance (LPR) and Electrochemical Impedance Spectroscopy (EIS), are reported in the literature as alternatives to the PDP [ 17 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Nonetheless, in order to retrieve the corrosion rate at the monitored area, EIS have to be interpreted with the help of Tafel slopes that are usually obtained from the PDP curves [ 17 , 21 ].…”