Elaboration and microstructural characterization of calcareous/ceria based composite on zinc substrate
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- 作者：F. Aiouaz ; M. Jeannin ; J. Creus ; B. Saidani
- 刊名：Protection of Metals and Physical Chemistry of Surfaces
- 出版年：2016
- 出版时间：September 2016
- 年：2016
- 卷：52
- 期：5
- 页码：894-899
- 全文大小：1,171 KB
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Chemistry
Tribology, Corrosion and Coatings
Materials Science
Metallic Materials
Inorganic Chemistry
Industrial Chemistry and Chemical Engineering
Characterization and Evaluation Materials - 出版者：MAIK Nauka/Interperiodica distributed exclusively by Springer Science+Business Media LLC.
- ISSN：2070-206X
- 卷排序：52
文摘
Cerium conversion coatings were prepared by cathodic electrodeposition from a low concentrated aqueous solution of Ce(NO3)3 with KNO3 addition to insure the conductivity of the electrolyte. The cerium oxide film was characterized by Scanning Electronic Microscopy (SEM). Although the deposit is uniform with current density of 2 mA/cm2, it shows cauliflower morphology with a crack network, giving rise to bad mechanical and electrochemical behaviour. Elaboration of a calcareous deposit inside crack network of the cerium coating by cathodic polarization from artificial seawater is investigated at different applied potential, in order to increase the quality of the cerium coating formed. For cathodic potentials lower than–1.5 V/SCE, zinc corrosion products (gordaite) were observed inside the cerium oxide film instead of calcareous deposit although the current density decrease during the deposition suggesting a partially blocked surface. A pure calcareous compound was observed at–1.5 and–1.6 V/SCE. SEM and EDX cartography of the cross section revealed that open cracks in the cerium oxide structure are filled by calcium. Calcium was also detected inside the CeO2 film not only all around the cracks but also in all the porosity of the CeO2 film. It has precipitated as CaCO3 (aragonite form) as revealed by micro-Raman spectroscopy and XRD.