Corrosion behaviour of cobalt-based coatings with ruthenium additions in synthetic mine water

Silas I. Hango; Lesley A. Cornish; Josias W. van der Merwe; Lesley H. Chown; Frank P.L. Kavishe

Results in Materials (Mar 2024)

Corrosion behaviour of cobalt-based coatings with ruthenium additions in synthetic mine water

Silas I. Hango,
Lesley A. Cornish,
Josias W. van der Merwe,
Lesley H. Chown,
Frank P.L. Kavishe

Affiliations

Silas I. Hango: School of Chemical and Metallurgical Engineering, DSI-NRF Centre of Excellence in Strong Materials and African Materials Science and Engineering Network (AMSEN): Hosted by the University of the Witwatersrand, Private Bag 3, WITS, 2050, Johannesburg, South Africa; Department of Mechanical and Metallurgical Engineering, University of Namibia, P.O. Box 3624, Ongwediva, Namibia; Corresponding author. Department of Mechanical and Metallurgical Engineering, University of Namibia, P.O. Box 3624, Ongwediva, Namibia.
Lesley A. Cornish: School of Chemical and Metallurgical Engineering, DSI-NRF Centre of Excellence in Strong Materials and African Materials Science and Engineering Network (AMSEN): Hosted by the University of the Witwatersrand, Private Bag 3, WITS, 2050, Johannesburg, South Africa
Josias W. van der Merwe: School of Chemical and Metallurgical Engineering, DSI-NRF Centre of Excellence in Strong Materials and African Materials Science and Engineering Network (AMSEN): Hosted by the University of the Witwatersrand, Private Bag 3, WITS, 2050, Johannesburg, South Africa
Lesley H. Chown: School of Chemical and Metallurgical Engineering, DSI-NRF Centre of Excellence in Strong Materials and African Materials Science and Engineering Network (AMSEN): Hosted by the University of the Witwatersrand, Private Bag 3, WITS, 2050, Johannesburg, South Africa
Frank P.L. Kavishe: Department of Mechanical and Metallurgical Engineering, University of Namibia, P.O. Box 3624, Ongwediva, Namibia

Journal volume & issue: Vol. 21
p. 100546

Abstract

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The corrosion behaviour of two cobalt-based coatings (ULTIMET™ and STELLITE™ 6) with zero, 0.3 and 0.6 wt% ruthenium were studied and compared with two cobalt-based bulk alloys (ULTIMET™ and STELLITE™ 6B) in synthetic mine water (pH values of 6, 3 and 1) using potentiodynamic polarisation. The coatings demonstrated wider ranges of passivation behaviour (from −250 mV to 750 mV) than the bulk alloys. The corrosion potential became more positive and the active-passive transition reduced with increased Ru. The best coating was STELLITE™ 6 with 0.6 wt% Ru, which exhibited the lowest corrosion rates: 3.6 μm/y at pH 6 and 6.4 μm/y at pH 3.

Published in Results in Materials

ISSN: 2590-048X (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials
Website: https://www.journals.elsevier.com/results-in-materials

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