Layer-by-layer analysis of hot-dip zinc coating by anodic dissolution in acetate bath
| Autor: | G. Roventi, Tiziano Bellezze, S. N. Saltykov, Romeo Fratesi, M. Malavolta |
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| Rok vydání: | 2012 |
| Předmět: |
Materials science
Layer by layer Inorganic chemistry chemistry.chemical_element Surfaces and Interfaces General Chemistry Zinc engineering.material Condensed Matter Physics Electrochemistry Surfaces Coatings and Films Anode chemistry Coating Chemical engineering Electrode Materials Chemistry engineering Polarization (electrochemistry) Dissolution |
| Zdroj: | Surface and Coatings Technology. 206:5023-5027 |
| ISSN: | 0257-8972 |
| DOI: | 10.1016/j.surfcoat.2012.04.008 |
| Popis: | To analyze the distribution of the alloying elements in hot-dip zinc coatings, a layer-by-layer electrochemical dissolution method was studied by using an acetate bath. The research was performed by means of galvanostatic anodic polarization, chemical analysis and metallographic analysis. A suitable cell was constructed to perform this study. Results show that the electrochemical dissolution of η-phase is uniform, while δ-phase dissolves partially together ζ-phase, due to the formation of cracks in the coating during polarization. Faraday's law was used to demonstrate that galvanostatic dissolution of hot-dip zinc coating at 12.7 mA cm − 2 proceeds by electrochemical mechanism without chemical dissolution; on the contrary, the occurrence of this second process was found at lower stripping current density. During polarization, the formation of a black film which interferes with the subsequent dissolution process was found. Mechanical removal of black film from electrode surface leads to the decrease of cracks formation and to a more uniform layer-by-layer dissolution. A method to obtain layer-by-layer analysis of the alloying elements of a hot-dip zinc coating, as a function of its thickness, by controlled electrochemical dissolution is suggested. |
| Databáze: | OpenAIRE |
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