INVESTIGATION OF NI-P COATINGS ON AZ91 CAST MAGNESIUM ALLOY

1 WASSERBAUER Jaromír
Co-authors:
1 BUCHTÍK Martin 1 BRESCHER Roman
Institution:
1 Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic, EU, wasserbauer@fch.vut.cz
Conference:
28th International Conference on Metallurgy and Materials, Hotel Voronez I, Brno, Czech Republic, EU, May 22nd - 24th 2019
Proceedings:
Proceedings 28th International Conference on Metallurgy and Materials
Pages:
1192-1196
ISBN:
978-80-87294-92-5
ISSN:
2694-9296
Published:
4th November 2019
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
29 views / 18 downloads
Abstract

In this paper, the preparation and characterization of as-deposited and heat-treated low phosphorus Ni-P coatings on AZ91 magnesium was performed. Heat-treated Ni-P coatings reached the higher microhardness of 1030 ± 20 HV 0.025 when compared to as-deposited Ni-P coatings (560 ± 20 HV 0.025). Using the scanning electron microscopy, the microstructure and surface morphology of Ni-P coatings was observed. Heat-treated coatings were formed by cracks network on their surface due to their crystallization during the heat-treatment. These cracks negatively affected the electrochemical and corrosion properties. However, as-deposited Ni-P coatings improved the electrochemical corrosion properties when compared to AZ91 alloy. The corrosion potential increased to -0.59 ± 0.02 V and the corrosion current density decreased to 1.4 ± 0.3 µA∙cm-2.

Keywords: Electroless Ni-P coating, AZ91, magnesium alloy, heat treatment, potentiodynamic polarization test
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