Effect of chloride concentration on the corrosion resistance of pure Zn metal in a 0.0626 M H2SO4 solution

Loto, R. T. (2023) Effect of chloride concentration on the corrosion resistance of pure Zn metal in a 0.0626 M H2SO4 solution. Open Engineering, 13.

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Abstract

The aftermath of Cl− anion concentration reactions on the corrosion resistance of pure Zn metal in 0.0625M H2SO4 was examined by potentiodynamic polarization, optical representations, scanning electron image analysis, energy dispersive X-ray (EDX) spectroscopy, open-circuit potential analysis, X-ray diffractometry, weight loss method and X-ray fluorescence. The results show that the degradation of Zn increased with an increase in the chloride concentration from 4.089 and 0.218mm/year to 10.085 and 4.015mm/year (polarization and weight loss). The corrosion potential at 0.0625M H2SO4 to 0.0625M H2SO4/0.5% NaCl concentration displayed minimal variation (−1.535 to −1.519 V), whereas a significant shift was observed for the plots at 0.0625M H2SO4/1% NaCl and 0.0625M H2SO4/2% NaCl (−1.384 and −0.932 V). The weight loss plot at all Cl− anion concentrations displayed an ordered decrease in the corrosion rate analogous to exposure times. The scanning electron microscopic images of Zn in 0.0625M H2SO4/2% NaCl solution showed significant deterioration and corrosion pits. The image at 0.0625M H2SO4 solution revealed limited localized and general surface deterioration, while the corresponding EDX data depict the presence of S. The Zn open-circuit potential plot from a 0.0625M H2SO4 solution was relatively electropositive compared to the plot from a 0.0625M H2SO4/ 2% NaCl solution. Both plots exhibited limited reactive-inert transition properties and attained relative thermodynamic equilibrium after 600 s of exposure with final corrosion potentials of −0.91 and −0.97 V at 7,200 s. Zn was the only crystallographic phase identified on its surface before corrosion, whereas ZnS, ZnFes, ZnMnS, ZnMnFeS, and ZnMg4 corrosion products were identified after corrosion.

Item Type:	Article
Uncontrolled Keywords:	zinc, corrosion management, NaCl, environmental degradation, H2SO4
Subjects:	T Technology > TJ Mechanical engineering and machinery T Technology > TP Chemical technology
Divisions:	Faculty of Engineering, Science and Mathematics > School of Engineering Sciences
Depositing User:	Patricia Nwokealisi
Date Deposited:	21 Jan 2025 10:05
Last Modified:	21 Jan 2025 10:05
URI:	http://eprints.covenantuniversity.edu.ng/id/eprint/18712

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