The corrosion behaviour of WC-VC-Co hardmetals in acidic media
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Date
2010-06-01
Authors
Konadu, D.S.
van der Merwe, J.
Potgieter, J.H.
Potgieter-Vermaak, S.
Machio, C.N.
Journal Title
Journal ISSN
Volume Title
Publisher
Corrosion Science
Abstract
The effect of increasing vanadium carbide (VC) content on the corrosion behaviour of tungsten carbide – 10 wt% cobalt hardmetals was investigated in 1 M hydrochloric (HCl), and sulphuric (H2SO4) acids solutions. Increasing VC content makes the open circuit potential (OCP) in the test solutions more negative than the base alloy. Specimens exhibited pseudo passivation in all the test solutions. Increasing VC led to decreasing corrosion current density. However, the corrosion current densities during chronoamperometric tests were lower for 0 wt% VC. XRD and Raman spectroscopy showed that hydrated WO3 formed in the surface films of all specimens in hydrochloric acid (HCl), while hydrated vanadyl sulphate also formed for higher VC content specimens in sulphuric acid (H2SO4).
Description
Keywords
WC-Co, WC-VC-Co, Polarisation, XRD, Raman Spectroscopy, Passivity
Citation
Corrosion Science, v 52, n 9, p 3118-3125, September 2010