An EIS study of ion diffusion through organic coatings

Deflorian, F.; Rossi, Stefano

doi:10.1016/j.electacta.2005.02.145

Cited by 117 publications

(77 citation statements)

References 20 publications

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“…the delaminated distance versus square root time is shown in Figure 7. In agreement with several other studies [6,11,40,41], the progress of the delamination front is clearly proportional with the square root of exposure time as a correlation coefficient greater than 0.99 is found. The observation that the progress of the delamination front is proportional with the square root of time suggest that interfacial diffusion along the coating-steel interface is likely to be the ratedetermining step of the process of cathodic delamination because the mean diffusion length, x , for a diffusion time, t, for linear isotropic and semi-infinite diffusion is given by [11] x=2 D t ⋅ ⋅…”

Section: Route Of Cationssupporting

confidence: 78%

Influence of substrate topography on cathodic delamination of anticorrosive coatings

Sörensen

Kiil

Dam‐Johansen

et al. 2009

Progress in Organic Coatings

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The cathodic delamination of a commercial TiO 2 pigmented epoxy coating on abrasive cleaned cold rolled steel has been investigated. The rate of delamination was found to depend on interfacial transport from the artificial defect to the delamination front and thereby the substrate topography, whereas the coating thickness had little influence. The presence of a significant potential gradient between the anode and the cathode and the dependency of the delamination rate on the tortuosity of the steel surface suggests that cathodic delamination is controlled by migration of cations from the defect to the delamination front. This means that abrasive blasting, to some extent, can be applied to control and minimize the observed rate of cathodic delamination. The lifetime of the species causing disbondment suggested that sodium hydroxide or potassium hydroxide and not peroxide species or radicals are the causative agents at free corrosion potential (i.e. without impressed current).

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Section: Route Of Cationssupporting

confidence: 78%

Influence of substrate topography on cathodic delamination of anticorrosive coatings

Sörensen

Kiil

Dam‐Johansen

et al. 2009

Progress in Organic Coatings

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“…Electrochemical studies.-EIS measurements.-EIS is a powerful tool that was widely used in the last few decades for the characterization of corrosion processes as well as for the assessment of the protective performance of pre-treatments, organic coatings [33][34][35][36][37][38][39][40][41][42][43][44][45] and OIH coatings. 46,47 This electrochemical technique is not destructive.…”

Section: Resultsmentioning

confidence: 99%

Alcohol-Aminosilicate Hybrid Coatings for Corrosion Protection of Galvanized Steel in Mortar

Figueira¹,

Silva²,

Pereira³

et al. 2014

J. Electrochem. Soc.

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Organic-inorganic hybrid (OIH) matrices were synthesized by sol-gel method and deposited on hot-dip galvanized steel (HDGS) using a dip-coating process. These OIHs, generally called amino-alcohol-silicates, were synthesized using a functionalized siloxane, 3-glycidoxypropyltrimethoxysilane, and five oligopolymers (Jeffamine) with different molecular weights: 230, 400, 600, 900 and 2000. Besides the five different pure OIH matrix coatings, a similar set of HDGS samples were coated with the OIH matrices doped with Cr(III), which was tested as a corrosion inhibitor. The OIH coatings were assessed using electrochemical studies, namely electrochemical impedance spectroscopy, macrocell current density, open circuit potential monitoring and polarization resistance. The studies were carried out in mortar. Analysis of the results obtained by optical and scanning electronic microscopy methods were consistent with the data obtained by electrochemical techniques. The HDGS samples coated with OIH matrices showed better performance when compared with HDGS uncoated samples. During the last three decades, the corrosion of steel reinforcement has been widely studied and reported. [1][2][3][4][5][6][7] In spite of the majority of the reinforced concrete (RC) structures showing high durability, serviceability and long-term performance as well as intense research being performed in the last few years, a large number of failures have been reported due to the corrosion of the reinforcement embedded in the concrete.The most effective way to minimize the risk of corrosion reinforcement concrete is to ensure that the cover of the metallic reinforcement parts is of an adequate thickness. The concrete should be of high quality, with a proper mixing ratio, good compaction and curing. 1,6,7 Several proven methods are known for preventing and controlling corrosion. Improving the concrete quality and increasing the concrete cover are the most economical protection measures yet are not always enough. A method that is widely accepted and recognized as efficient at providing corrosion protection of the RC structures is the application of hot-dip galvanized steel (HDGS), since it is considered economically favorable when compared to others. The use of HDGS has been recognized by several authors 7,[8][9][10][11][12] as an effective measure to increase the service life of RC structures exposed to carbonation or to chloride ions. However, zinc in contact with fresh concrete (high alkaline environment) is oxidized and hydrogen evolution occurs, for a limited period, until passivating formation layers occur and concrete hardens. To avoid zinc corrosion and hydrogen evolution, chromate and similar hexavalent chromium compounds are among the most common substances used as inhibitors or incorporated into the preparation of the fresh concrete. However, these compounds are toxic and carcinogenic, causing serious environmental hazards and their incorporation in protective coatings is heavily regulated by most environmental legislation. Therefore, intense re...

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“…The process of cathodic delamination is another most significant causes of film degradation [111]. The bulk amount of atmospheric pollutants at the film defect is the source of many corrosive species that take part in the electrolytic alkalinisation of solution as shown in fig.…”

Section: Cathodic Delaminationmentioning

confidence: 99%

A review of theoretical analysis techniques for cracking and corrosive degradation of film-substrate systems

Nazir

Khan

2017

Engineering Failure Analysis

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This paper contains a review of the most vital concepts regarding the analysis and design of film systems. Various techniques have been presented to analyse and predict the failure of films for all common types of failure: fracture, delamination, general yield, cathodic blistering, erosive and corrosive wear in both organic and inorganic films. Interfacial fracture or delamination is the loss of bonding strength of film from substrate, and is normally analysed based on the fracture mechanics concepts of bi-material systems. Therefore, keeping the focus of this review on bonding strength, the emphasis will be on the interfacial cracking of films and the corresponding stresses responsible for driving the delamination process. The bi-material characteristics of film systems make the nature of interfacial cracks as mixed mode, with cracks exhibiting various complex patterns such as telephone cord blisters. Such interfacial fracture phenomenon has been widely studied by using fracture mechanics based applicable analysis to model and predict the fracture strength of interface in film systems. The incorporation of interfacial fracture mechanics concepts with the thermodynamics/diffusion concepts further leads to the development of corrosive degradation theories of film systems such as cathodic blistering. This review presents the suggestions for improvements in existing analysis techniques to overcome some of the limitations in film failure modelling. This comprehensive review will help researchers, scientists, and academics to understand, develop and improve the existing models and methods of film-substrate systems.

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An EIS study of ion diffusion through organic coatings

Cited by 117 publications

References 20 publications

Influence of substrate topography on cathodic delamination of anticorrosive coatings

Influence of substrate topography on cathodic delamination of anticorrosive coatings

Alcohol-Aminosilicate Hybrid Coatings for Corrosion Protection of Galvanized Steel in Mortar

A review of theoretical analysis techniques for cracking and corrosive degradation of film-substrate systems

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