EIS measurements on artificial blisters in organic coatings

Weijde, D.H. van der; Westing, E.P.M. van; Wit, J.H.W. de

doi:10.1016/0013-4686(95)00444-0

Cited by 38 publications

(8 citation statements)

References 11 publications

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“…From Bode plots in Figure 7(b), as the increase of the current density, the impedance of the coating increased. EIS plots have been shown to be an electrochemical process associated with corrosion reaction and deposition of corrosion products in the presence of large coating defects [33]. Walkner and Hassel [34] noted that the increased or decreased of the impedance represents the process of the formation or decomposition of the corrosion product film, respectively, with occasionally one of both processes being dominant.…”

Section: Eis Analysismentioning

confidence: 99%

Effects of stray AC on corrosion of 3-layer polyethylene coated X70 pipeline steel and cathodic delamination of coating with defects in 3.5 wt-% NaCl solution

Wang

Chen

et al. 2018

Corrosion Engineering, Science and Technology

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In this work, the effects of stray alternating current (AC) on the corrosion of coated X70 pipeline steel and the delamination of 3-layer polyethylene (3PE) coatings with defects were investigated using COMSOL Multiphysics simulation, electrochemical impedance spectroscopy and three-dimensional (3D) digital microscope techniques. The results showed that under the same level of AC interference, pits with deeper maximum pit depth were observed at the smaller defect areas than those at larger defect areas. It was consistent with the simulation results that a greater corrosion current density was accompanied on samples with smaller defects. According to 3D digital images, the larger delamination of 3PE coatings was found on samples with smaller defects. With the increase of current density, the impedance of samples with small defects decreased, while that of samples with large defects increased. Additionally, with the same defect size, the maximum pit depth became deeper and the corrosion was more severe.

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Section: Eis Analysismentioning

confidence: 99%

Effects of stray AC on corrosion of 3-layer polyethylene coated X70 pipeline steel and cathodic delamination of coating with defects in 3.5 wt-% NaCl solution

Wang

Chen

et al. 2018

Corrosion Engineering, Science and Technology

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“…The cathodic delamination at scratch line front and anodic reaction at the scratch could coexist at the same time. This implies that the corrosion mechanism is a complex process in the scratched area of the epoxy coated carbon steel and depends on the type of metal/alloy, its chemical composition and ability to form a passive film, defect size, concentration of Clions, transport phenomena and the nature of corrosion products [36][37][38]. The experimental results of the present study as well as the LEIS maps provides a better insight on local corrosion mechanism of scratched epoxy coated carbon steel in SPS containing varying % of Clions.…”

Section: Leis Mapping Performed At Scratched Epoxy Coated Carbon Steelmentioning

confidence: 99%

In-Situ Monitoring of Local Corrosion Process of Scratched Epoxy Coated Carbon Steel in Simulated Pore Solution Containing Varying percentage of Chloride ions by Localized Electrochemical Impedance Spectroscopy

Balusamy

Nishimura

2016

Electrochimica Acta

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The present work focuses on the corrosion behaviour of scratched epoxy coated carbon steel in simulated pore solution (SPS) containing varying % of chloride ions (added as NaCl) by localized electrochemical impedance spectroscopy (LEIS). LEIS results indicate that the |Z| at the scratch is decreased significantly with an increase in % of Clions in SPS, which is evidenced by the formation of a depressed semicircle in the LEIS Nyquist plots. The intermediate corrosion products involved in the local corrosion process appears to be a function of the % of Clions present in SPS. The competition between the aggressive Clions and the inhibitive OHions and the extent of decrease in pH at interface determines the rate of corrosion. The LEIS maps acquired at 10 Hz provides a better understanding of the involvement of the anodic and cathodic areas on the local corrosion process of scratched epoxy coated carbon steel. The continuous decrease in |Z| at the scratch is due to the higher extent of dissolution of Fe at the scratch while the change in |Z| over the coating is determined by the extent of dissolution of Fe and accumulation of corrosion products over the coating due to the high bulk pH of SPS. No significant decrease in |Z| at the scratch is observed when the % of Clions in SPS is 0.05. However, when the % of Clions in SPS is increased beyond 0.05%, a significant increase in the corrosion rate of scratched epoxy coated carbon steel is observed. Hence, 0.05% NaCl can be considered as a threshold level of chloride ions in SPS. A pictorial model is proposed to explain the local corrosion process and mechanism of scratched epoxy coated carbon steel in chloride containing SPS.

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“…These blisters can be as large as several millimeters. These are a type of visible failure originating from the corrosion at the coating/steel substrate interface as well as deteriorated coating performance [2][3][4][5]. The occurrence of blisters may be considered the ultimate index of the lifetime for high-performance and quality coatings without initial defects.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Accelerated Degradation Methods to Cause Blisters for Non-Defective Vinyl Ester Resin Glass Flake Organic Coatings

2022

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Organic coatings are applied as a corrosion prevention measure, but their effectiveness may degrade over time. In this study, the acceleration effects of typical degradation methods in non-defective vinyl ester resin organic coatings containing glass flakes such as high-temperature immersion and immersion in chemical accelerators are clarified using physiochemical techniques. Immersion in an acetic acid (AcOH) aqueous solution causes resin swelling, and the behaviors are quantitatively evaluated through gravimetric, thickness, and electrochemical impedance spectroscopy (EIS) measurements. Furthermore, a combined process of immersion in hydrofluoric acid and an AcOH aqueous solution reduces the electrical properties and eventually blisters the thick coating surface. This result suggests that an appropriate combination of the resin swelling and the glass degradation (glass dissolution and/or formation of the gap between glass and resin) decrease mechanical properties of the glass flake coating and causes blisters. In order to help the health diagnosis of the visually non-defective aged glass flake coating, the relationship between the electrical characteristic values and the invisible degradation by accelerated tests is finally indicated.

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EIS measurements on artificial blisters in organic coatings

Cited by 38 publications

References 11 publications

Effects of stray AC on corrosion of 3-layer polyethylene coated X70 pipeline steel and cathodic delamination of coating with defects in 3.5 wt-% NaCl solution

Effects of stray AC on corrosion of 3-layer polyethylene coated X70 pipeline steel and cathodic delamination of coating with defects in 3.5 wt-% NaCl solution

In-Situ Monitoring of Local Corrosion Process of Scratched Epoxy Coated Carbon Steel in Simulated Pore Solution Containing Varying percentage of Chloride ions by Localized Electrochemical Impedance Spectroscopy

Investigation of Accelerated Degradation Methods to Cause Blisters for Non-Defective Vinyl Ester Resin Glass Flake Organic Coatings

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