Analytical Characterization of the Corrosion Mechanisms of WC-Co by Electrochemical Methods and Inductively-Coupled Plasma Mass Spectroscopy

Abstract

WC-Co exhibit a rather high susceptibility to corrosion in aqueous solutions, which is a result of complex reaction mechanisms. The local distribution of the surface reactions is thus of considerable interest. Electrochemical measurements provide only a one-sided information about the corrosion processes. For this purpose, comparative studies of elemental solution analysis by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) were carried out. The use of a flow cell allowed simultaneous online detection of dissolving elements. Surface characterization by XPS was used to determine the influence of solution contact on the surface composition. In order to elucidate the local aspects of the WC- Co corrosion behaviour, conventional electrochemical results (potentiodynamic polarization measurements) were compared to experiments, performed with a micro-capillary technique, which provides a focused view on the local corrosion situation. From these different methods, a more conclusive model presentation of the reaction mechanisms, taking place on WC-Co in aqueous solution, is proposed.

Corrosion Resistance of Tungsten-Carbide-Rich Coating Layers Produced by Noble Gas Ion Mixing

“…Moreover, the selective dissolution of carbides and tungsten phase in chlorine environment have been reported by several authors [7,[30][31][32]. These findings suggest that the processes at the positive side of the voltammograms can be attributed to the dissolution of tungsten and tungsten carbide.…”

Indentation and scratch testing of a WC-6%wtCo cemented carbide: Corrosion effects on load-bearing capability and induced damage

“…In this regard, extensive research has proven that corrosion significantly affects microstructural and mechanical/tribological characteristics of cemented carbides. Regarding the former, it is well-known that the original microstructural scenario is changed, through dissolution of different individual phases depending on acidic or basic nature of the media [9][10][11][12][13][14]. Concerning the latter, it is established that rupture, wear and fatigue resistance of corroded hardmetals decrease [5,10,[15][16][17][18][19][20][21].…”

Comparison of corrosion, physico-mechanical and wear properties of TiN, ZrN, TixZr1-xN and Ti1-xAlxN coatings

“…Electrochemical tests (polarization curves, electrochemical impedance spectroscopy (EIS)) were performed in 5% NaOH. Coating defects can be more detectable in a NaOH solution due to the more significant dissolution of hard alloy in alkaline media [5]. The electrodes for electrochemical measurements were embedded in epoxy, leaving only one side of the sample in contact with the solution.…”