Investigation of Service Life Prediction Models for Metallic Organic Coatings Using Full-Range Frequency EIS Data

Abstract

Abstract:Various service life prediction models of organic coatings were analyzed based on the acquirement of the measurement of Electrochemical Impedance Spectroscopy (EIS) from indoor accelerated tests. First, some theoretical formulas on corrosion lifetime predictions of coatings were introduced, followed by the comparative assessment of four practical prediction models in view of prediction accuracy in application. The prediction from impedance data at single low frequency |Z| 0.1 Hz , the classical degradation kinetics, and proposed improved degradation kinetics model, as well as a self-organized neural network prediction based on sample detection, were focused in this paper. The standard AF1410 plates employed as the metallic substrates were coated with sprayed zinc layer, epoxy-ester primer and polyurethane enamel layer. The accelerated experiments which mimicked coastal areas of China were carried out with the specimens after surface treatment. The assessment of results showed that the proposed improved degradation kinetics model and neural network classification model based on the full range of frequency data obviously have higher prediction accuracies than the traditional degradation kinetics model, and the prediction precision of the sample detection-based neural network classification was the highest among these models. The study gives some insights for coating degradation lifetime prediction which may be useful and supportive for practical applications.

Polysilazane-based coatings: corrosion protection and anti-graffiti properties

“…FT-IR analyses have been recorded on a Varian 4100 FTIR Excalibur Series instrument, exploiting the attenuated total reflectance (ATR) geometry in the wavenumber range 4000–500 cm −1 (64 scans, 4 cm −1 resolution) using a diamond crystal as an internal reflective element. To gather information about the covering efficiency and protection properties of the deposits, EIS [25] measurements have been carried out. A frequency range of 10 5 –10 −2 Hz with amplitude of signal of 5 mV (rms) have been used.…”

Surface electroanalytical approaches to organic polymeric coatings

“…EIS is used to extract mechanistic information on the charge-transfer activities at the coating-metal interface and various degradation mechanisms that lead to coating delamination or loss in adhesion. 15,17,[27][28][29][30] A perfectly coated metal is an electrical capacitor where the coating is an insulating dielectric material sandwiched between two conductor materials: metal on one side and the electrolyte solution on the other. 47 Therefore, in its pristine form, a coated metal will have the electrical response of a capacitor.…”

“…25,26 Techniques that measure impedance and the correlation between current, potential and time have been widely used to obtain mechanistic information on corrosion. 15,17,[27][28][29][30][31][32][33][34][35][36][37][38] Hence, this mini-review briefly explores the most commonly used electrochemical techniques in the evaluation of corrosion protection performance of polymeric coatings: open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, electrochemical noise and scanning electrochemical microscopy (SECM). The mode of operation, acquisition of data, relevant equations and electrochemical variables, as well as the advantages and shortcomings of each technique, are also highlighted.…”

Prediction of long-term service life of an organic coating based on short-term exposure results

“…Many simulated and accelerated corrosion tests (Sun et al , 2015; Xu et al , 2017) have been used to measure these parameters, such as the wet-day cycles (Skerry and Simpson, 1993; Qu et al , 2019), thermal cycles (Touzain et al , 2005), freezing test (Perrin et al , 2009), ultraviolet (UV) exposure (Deflorian et al , 2007), UV-condensation (Bedoya et al , 2014), copper ion acceleration (Zuo et al , 2018), solvent-wipe (Mao et al , 2013) and water boiling (Wu et al , 2012). Particularly, electrochemical methods (Rodríguez et al , 2004), e.g.…”