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Corrosion mechanism of tungsten carbide-based coatings in different aqueous media

Kamdi, Zakiah and Voisey, K. T. (2015) Corrosion mechanism of tungsten carbide-based coatings in different aqueous media. In: 24th Scientific Conference of the Microscopy Society Malaysia (SCMSM 2015), Hotel Avillion, Melaka, Malaysia, 2-4 December 2015.

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Abstract

In cermet coatings with both ceramic and metal present, these can have very different corrosion potentials. Therefore, determination of the corrosion behaviour performance and its mechanism is crucial, especially in very acidic and alkaline environment. A conventional high velocity oxy-fuel (HVOF) tungsten carbide (WC)-Co coatings and a weld overlay tungsten carbide-nickel alloy cermet with carbide size of ~0.3-5 µm and ~50-140 µm respectively are used. Potentiodynamic tests are carried out in acidic and alkaline electrolytes: 0.5 M sulphuric acid, pH 0.45 and bentonite drilling fluid, pH 10.45. The behaviour of both coating types tested were pH dependent. The HVOF coating showed preferential dissolution of the binder in both electrolytes, with material loss being approximately twice as severe in the 0.5 M sulphuric acid compared to the alkaline drilling fluid. For the weld overlay coatings, with the larger carbide particles, the Ni3B phase in the binder was preferentially removed in the acidic electrolyte whereas the Ni rich dendritic phase underwent preferential dissolution in the alkaline environment

Item Type: Conference or Workshop Item (Paper)
Uncontrolled Keywords: corrosion; cermet; drilling fluid
Subjects: T Technology > T Technology (General)
Divisions: Faculty of Mechanical and Manufacturing Engineering > Department of Materials Engineering and Design
Depositing User: Mrs. Nurhayati Ali
Date Deposited: 13 Aug 2018 03:41
Last Modified: 13 Aug 2018 03:41
URI: http://eprints.uthm.edu.my/id/eprint/7682
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