Effect of KOH Content in the Electrolyte on Corrosion Properties of PEO-Coated EV31 Magnesium Alloy

Effect of KOH Content in the Electrolyte on Corrosion Properties of PEO-Coated EV31 Magnesium Alloy

KNAP Vidžaja, OBERTOVÁ Veronika, HADZIMA Branislav

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Abstract. This study analyzed the influence of electrolyte composition on the corrosion resistance of plasma electrolytic oxidation (PEO) coatings on EV31 magnesium alloy. An electrolyte solution was prepared by mixing 12 g/l Na3PO4 and various levels of KOH (1, 2, and 4 g/l). The PEO coating was produced with a direct current (DC) regime of 0.05 mA.cm-2 current density and a maximum voltage of 630 V. Electrochemical impedance spectroscopy was performed to assess the corrosion resistance after one hour exposure in 0.1 M NaCl. The results indicated that KOH content has a substantial effect on the morphology and corrosion resistance of the PEO coating and align with previous similar studies. The lowest porosity and highest polarization resistance were observed in the PEO coating prepared with 2 g/l of KOH in the electrolyte, resulting in the best corrosion resistance among the evaluated samples. The presence of only one capacitive loop in the Nyquist diagram and low polarization resistance Rp values of the samples with 4 g/l of KOH in the electrolyte indicated insufficient compactness due to high porosity of the coating.

Plasma Electrolytic Oxidation, PEO, Corrosion, EV31 Magnesium Alloy, Electrochemical Impedance Spectroscopy

Published online 9/1/2023, 7 pages
Copyright © 2023 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: KNAP Vidžaja, OBERTOVÁ Veronika, HADZIMA Branislav, Effect of KOH Content in the Electrolyte on Corrosion Properties of PEO-Coated EV31 Magnesium Alloy, Materials Research Proceedings, Vol. 34, pp 95-101, 2023

DOI: https://doi.org/10.21741/9781644902691-12

The article was published as article 12 of the book Quality Production Improvement and System Safety

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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