TEM and ToF-SIMS studies on the corrosion behavior of vanadium and chromium containing WC-Co hard metals in alkaline solutions

Beitrag in einer Fachzeitschrift


Details zur Publikation

Autorinnen und Autoren: Kellner F, Killian M, Yang G, Spiecker E, Virtanen S
Zeitschrift: International Journal of Refractory Metals and Hard Materials
Verlag: Elsevier BV
Jahr der Veröffentlichung: 2011
Band: 29
Heftnummer: 3
Seitenbereich: 376-383
ISSN: 0958-0611


Abstract

The corrosion behavior of hard metals with VC and Cr$_3$C$_2$ grain growth inhibitors was investigated in alkaline solutions by electrochemical methods. The two inhibitors have opposite effects on the corrosion behavior: Cr$_3$C$_2$ significantly improves the corrosion behavior, whereas VC-containing alloys show a poor resistance. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and analytical transmission electron microscopy (TEM) analyses of the distributions of Cr and V in the composite material, as well as in the surface layers formed during corrosion were employed to clarify the influence of these elements on the corrosion behavior. The measurements showed that VC is precipitated mostly along the WC/binder interface after the liquid-phase sintering process, while Cr$_3$C$_2$ is almost homogeneously dissolved in the binder. As VC is chemically instable in alkaline solutions, it completely dissolves out of the binder. In accordance with this observation no V was found in the corrosion product layer on the surface. As WC is more noble than Co, galvanic coupling between the two phases reinforces the Co dissolution, while the WC-phase is protected cathodically. Contrary to VC, chromium is stable in alkaline environments and forms a passivating Cr$_2$O$_3$ layer. Enrichment of Cr in the corrosion product layers was detected by TEM and ToF-SIMS. Due to surface passivation by Cr$_2$O$_3$, galvanic coupling effects between Co and WC play a much less important role in the corrosion process of the composite material.


FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

Killian, Manuela Dr.-Ing.
Lehrstuhl für Werkstoffwissenschaften (Korrosion und Oberflächentechnik)
Spiecker, Erdmann Prof. Dr.
Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)
Virtanen, Sannakaisa Prof. Dr.
Professur für Werkstoffwissenschaften (Korrosion und Oberflächentechnik)


Zusätzliche Organisationseinheit(en)
Interdisziplinäres Zentrum, Center for Nanoanalysis and Electron Microscopy (CENEM)
Exzellenz-Cluster Engineering of Advanced Materials


Forschungsbereiche

A2 Nanoanalysis and Microscopy
Exzellenz-Cluster Engineering of Advanced Materials


Zitierweisen

APA:
Kellner, F., Killian, M., Yang, G., Spiecker, E., & Virtanen, S. (2011). TEM and ToF-SIMS studies on the corrosion behavior of vanadium and chromium containing WC-Co hard metals in alkaline solutions. International Journal of Refractory Metals and Hard Materials, 29(3), 376-383. https://dx.doi.org/10.1016/j.ijrmhm.2011.01.008

MLA:
Kellner, Florian, et al. "TEM and ToF-SIMS studies on the corrosion behavior of vanadium and chromium containing WC-Co hard metals in alkaline solutions." International Journal of Refractory Metals and Hard Materials 29.3 (2011): 376-383.

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