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Insitu SVET studies on the current density distribution on dissolving of Mg, MgZn2, Mg2Si and Al4Cu2Mg8Si7 surfaces in NaCl solutions

Alexander I. Ikeuba (Department of Pure and Applied Chemistry, University of Calabar, Calabar, Nigeria)
Peter C. Okafor (University of Calabar, Calabar, Nigeria)
Benedict Ita (University of Calabar, Calabar, Nigeria)
Anthony I. Obike (Abia State University, Uturu, Nigeria)
Fidelis E. Abeng (Department of Chemistry, Cross River State University of Technology, Calabar, Nigeria)
Uduak Essien (University of Calabar, Calabar, Nigeria)
Abiola Bamigbola (University of Calabar, Calabar, Nigeria)

Anti-Corrosion Methods and Materials

ISSN: 0003-5599

Article publication date: 23 November 2021

Issue publication date: 3 January 2022

87

Abstract

Purpose

This paper aims to acquire the current density distribution on dissolving of Mg, MgZn2 (η -phase), Mg2Si (ß-phase) and Al4Cu2Mg8Si7 (Q-phase) surface in NaCl solutions.

Design/methodology/approach

MgZn2 (η -phase), Mg2Si (ß-phase) and Al4Cu2Mg8Si7 (Q-phase) are important intermetallic compounds found in aluminum alloys. Insitu scanning vibrating electrode technique (SVET) was used to acquire the current density distribution on dissolving of Mg, MgZn2 (η -phase), Mg2Si (ß-phase) and Al4Cu2Mg8Si7 (Q-phase) surface in NaCl solutions scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) was used to characterize the corroded surface.

Findings

SVET maps reveal that these compounds display characteristic dissolution features. Mg and MgZn2 displayed localized anodic and cathodic sites while that of Al4Cu2Mg8Si7 > Mg2Si displayed a diffused distribution of anodic and cathodic sites. The magnitude of the integrated anodic current densities on the compounds was noted to decrease with the progress of time, and the order of the magnitude of the current density with respect to the compounds is Mg > Mg2Si > Al4Cu2Mg8Si7 > MgZn2. SEM/EDX reveal that the highest mass loss recorded after the SVET test was manifested by Mg2Si followed by MgZn2 then Al4Cu2Mg8Si7.

Originality/value

Auxiliary information on the current density distribution on the corroding sample surface at the microscopic scale has been provided by SVET thereby taking care of certain limitations of traditional corrosion monitoring techniques such as gravimetric, hydrogen evolution and electrochemical measurements.

Keywords

Citation

Ikeuba, A.I., Okafor, P.C., Ita, B., Obike, A.I., Abeng, F.E., Essien, U. and Bamigbola, A. (2022), "Insitu SVET studies on the current density distribution on dissolving of Mg, MgZn2, Mg2Si and Al4Cu2Mg8Si7 surfaces in NaCl solutions", Anti-Corrosion Methods and Materials, Vol. 69 No. 1, pp. 104-110. https://doi.org/10.1108/ACMM-07-2021-2518

Publisher

:

Emerald Publishing Limited

Copyright © 2021, Emerald Publishing Limited

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