Comparative study on the degradation of a zinc-rich epoxy primer/acrylic polyurethane coating in different simulated atmospheric solutions / Wei Sun in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 18, N° 2 (03/2021)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 18, N° 2 (03/2021) . - p. 397–413 Titre : Comparative study on the degradation of a zinc-rich epoxy primer/acrylic polyurethane coating in different simulated atmospheric solutions Type de document : texte imprimé Auteurs : Wei Sun, Auteur ; Chao Xing, Auteur ; Xiaobo Tang, Auteur ; Yu Zuo, Auteur ; Yuming Tang, Auteur ; Xuhui Zhao, Auteur Année de publication : 2021 Article en page(s) : p. 397–413 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Atmosphère marine Copolymère uréthane acrylique Corrosion Epoxydes Primaire (revêtement) Revêtements -- Détérioration Revêtements organiques Spectroscopie d'impédance électrochimique Zinc Index. décimale : 667.9 Revêtements et enduits Résumé : The degradation of a zinc-rich epoxy primer/acrylic polyurethane coating system on carbon steel was studied in the simulated marine atmospheric solution (0.05% NaCl), industrial atmospheric solution (0.35% (NH4)2SO4), and marine-industrial atmospheric solution (0.05% NaCl + 0.35% (NH4)2SO4), by electrochemical impedance spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy methods. The influences of the soluble contaminants in the atmospheres, including chloride ions, sulfate ions, and ammonium ions, on the coating failure mechanism were compared and analyzed. The results showed that the degradation speed of the coating system in three simulated atmospheric solutions is in the following order: simulated marine atmosphere > simulated marine-industrial atmosphere > simulated industrial atmosphere. The degradation is mainly related to the permeation rate of the water through the coating. The aggressive ions, basic cations, and the property of the corrosion products also have influences on the degradation process. The alternating temperature environment (45°C 12 h + 25°C 12 h) could increase the degradation speed of the coating and the difference of the speed in the three solutions. Note de contenu : - EXPERIMENTAL : Materials and samples preparation - Corrosion tests and measurements - - RESULTS AND DISCUSSION : EIS results and the morphology of the coatings - FTIR results and SEM morphology of the coatings - Table 1 : Coating specifications - Table 2 : The impedance parameters of the coating sample in 0.05% NaCl solution under alternating hot and cold temperature condition - Table 3 : The impedance parameters of the coating sample in 0.35% (NH4)2SO4 solution under alternating hot and cold temperature condition - Table 4: The impedance parameters of the coating sample in 0.05% NaCl + 0.35% (NH4)2SO4 solution under alternating hot and cold temperature condition DOI : https://doi.org/10.1007/s11998-020-00410-8 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-020-00410-8.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35603 [article]

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Degradation of zinc-rich epoxy coating in 3.5% NaCl solution and evolution of its EIS parameters / Chao Xing in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 18, N° 3 (05/2021)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 18, N° 3 (05/2021) . - p. 843-860 Titre : Degradation of zinc-rich epoxy coating in 3.5% NaCl solution and evolution of its EIS parameters Type de document : texte imprimé Auteurs : Chao Xing, Auteur ; Wei Wang, Auteur ; Shuai Qu, Auteur ; Yuming Tang, Auteur ; Xuhui Zhao, Auteur ; Yu Zuo, Auteur Année de publication : 2021 Article en page(s) : p. 843-860 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Epoxydes Humidité -- Absorption:Eau -- Absorption Matériaux -- Propriétés barrières Porosité Protection cathodique Revêtements -- Détérioration Revêtements organiques Spectroscopie d'impédance électrochimique Test d'immersion Zinc Index. décimale : 667.9 Revêtements et enduits Résumé : The electrochemical characteristics in the degradation process of epoxy zinc-rich coating (80 wt% zinc particles) and epoxy varnish coating in 3.5% NaCl solution were studied comparatively by using open-circuit potential and electrochemical impedance spectroscopy tests. The coating morphology, the consumption and corrosion products of zinc particles and chemical changes in the coatings were observed and analyzed with the methods of scanning electron microscopy and X-ray diffraction. The results show that the zinc-rich coating provides effective cathodic protection to the carbon steel substrate at the initial stage and still provides certain cathodic protection in the period when the barrier protection by the formation of zinc corrosion products begins to dominate. Because the zinc particles are conductive and active, the values of the coating resistance and capacitance of zinc-rich coatings are lower than those of the varnish coating. When the value of |Z|0.01Hz decreases to 8 × 104 Ω cm2, the zinc-rich coatings still provide protection to the steel substrate, but when the value decreases to about 2 × 104 Ω cm2, rusted spots were observed on the coating surface. Based on the results, a reference criterion of failure for the zinc-rich epoxy coatings is suggested to be about 5 × 104 Ω cm2 (2 × 104 – 8 × 104 Ω cm2), which is different from the one (106 Ω cm2) reported in the literature for typical organic coatings without conductive particles. Note de contenu : - EXPERIMENTAL : Materials and samples preparation - Methods - Calculation of coating porosity and water absorption - RESULTS AND DISCUSSION : OCP measurements - EIS plots of the coating samples and the SEM analysis - EIS fitting results and analysis of the impedance parameters - SEM morphology of the zinc-rich epoxy coatings and consumption of zinc particles - FTIR results of the coatings - Table 1 : The equivalent electrical circuits of the coating samples in different immersion periods - Table 2 : EDS results of zinc-rich epoxy coating (90 μm) after 76 d of immersion - Table 3 : EDS results of zinc-rich epoxy coating (90 μm) after 287 d of immersion DOI : https://doi.org/10.1007/s11998-020-00448-8 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-020-00448-8.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35934 [article]

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