Evaluation of Corrosion Behavior of Coated Metals with AC Impedance Measurements

Mansfeld, F.; Kendig, M.; Tsai, S.

doi:10.5006/1.3577363

Cited by 357 publications

(131 citation statements)

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“…7 and 8 show the variation of pore resistance values of pigmented and unpigmented systems, respectively, with time for the three different phosphating conditions. Pore resistance of all the coatings followed a general decreasing trend with increasing exposure time as was reported earlier by other investigators [2,9,10]. For.…”

Section: Adhesion Testsupporting

confidence: 70%

Evaluation of blistering performance of pigmented and unpigmented alkyd coatings using electrochemical impedance spectroscopy

Raja

Devi

Venugopal

et al. 1998

Surface and Coatings Technology

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Section: Adhesion Testsupporting

confidence: 70%

Evaluation of blistering performance of pigmented and unpigmented alkyd coatings using electrochemical impedance spectroscopy

Raja

Devi

Venugopal

et al. 1998

Surface and Coatings Technology

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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 chemical stability of the phosphate coatings may be determined by exposing the coatings in dilute solution of sodium hydroxide and checking the extent of solubility [19,21]. The final corrosion performance of phosphated and painted surface maybe evaluated by accelerated tests like salts spray (ASTM-B117) and also by Electrochemical impedance Spectroscopy (EIS] [22][23][24][25][26][27]. In automotive industry, salts spray tests are widely used to evaluate the performance of phosphated (PT) and Electro-deposited primer (ED) coating.…”

Section: Characterization Of Phosphate Coatingmentioning

confidence: 99%

Importance of Surface Preparation for Corrosion Protection of Automobiles

Debnath¹

2013

JSEMAT

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An overview of science and technology of pretreatment process suitable for automotive finishing with cathodic electrodeposition primer is presented in details in this paper. Both the theoretical principles and practical aspects of tricationic phosphating process that are used in automotive industry are discussed in details. The characteristic features of phosphate coatings of both conventional high zinc phosphating formulations and modern tricationic phosphating formulations on steel surface are compared in details by SEM, EDX and XRD techniques. The corrosion protections of the phosphated and painted steel panels were evaluated by both salt spray test and electrochemical impedance spectroscopy (EIS). The analysis of impedance data in terms of pore resistance (Rpo), coating capacitance (Cc) and breakpoint frequency (f b ) as a function of salt spray exposure time provides a clear insight into the mechanism of superior corrosion resistance provided by the modern tricationic phosphating formulations compared with conventional high zinc phosphating formulations.

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Evaluation of Corrosion Behavior of Coated Metals with AC Impedance Measurements

Cited by 357 publications

References 0 publications

Evaluation of blistering performance of pigmented and unpigmented alkyd coatings using electrochemical impedance spectroscopy

Evaluation of blistering performance of pigmented and unpigmented alkyd coatings using electrochemical impedance spectroscopy

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

Importance of Surface Preparation for Corrosion Protection of Automobiles

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