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Effect of Hg2+ on the corrosion behavior of Al-2%Zn coatings on AA5083 in 3.5 Wt.% NaCl solution.
- Source :
-
Anti-Corrosion Methods & Materials . 2022, Vol. 69 Issue 3, p261-268. 8p. - Publication Year :
- 2022
-
Abstract
- Purpose: This paper aims to study the effect of Hg2+ on the corrosion behavior of Al–2%Zn coatings on AA5083 in 3.5 Wt.% NaCl solution. Design/methodology/approach: Potentiodynamic polarization and electrochemical impedance spectroscopy are used to investigate the effect of Hg2+ on the corrosion behavior. The surface and cross-sectional morphology are characterized by scanning electron microscopy and energy dispersive spectroscopy (EDS) to further reveal the corrosion mechanism of Hg2+. Findings: The results show that the corrosion behavior of the coating changes significantly as the concentration of Hg2+ increases from 5 to 30 μg/L. The corrosion production film can inhibit the corrosion process when Hg2+ concentration is in the range of 0.5–5 μg/L, while Hg2+ can promote the corrosion process significantly when its concentration reaches to 30 μg/L. The generation rate of dense oxide film on the coating surface is faster than dissolution rate when the concentration of Hg2+ is in the range of 0–5 μg/L, which makes the coating "self-healing" and thus slightly slows down the corrosion rate. The EDS analysis shows that excessive Hg2+ are preferentially deposited at locations with inhomogeneous electrochemical properties, which in turn accelerates corrosion. Originality/value: The corrosion resistance of Al-based coatings is significantly affected by Hg2+ in seawater. Thus, it is important to explain the corrosion mechanism of Al–2%Zn coatings under the combined effect of Hg2+ and Cl− in 3.5 Wt.% NaCl solution. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00035599
- Volume :
- 69
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- Anti-Corrosion Methods & Materials
- Publication Type :
- Academic Journal
- Accession number :
- 156267345
- Full Text :
- https://doi.org/10.1108/ACMM-10-2021-2553