Electrical discharge machining of ZrO2 toughened WC composites

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Abstract

The interrelationships between the dispersion of the ZrO2 phase and the electrical discharge machining (EDM) behaviour of WC based composites with 0, 5 or 10 vol% of ZrO2 are investigated. Special attention was given to the homogeneity of the ultrafine WC – nanometric ZrO2 powder based composites which were fully densified by means of pulsed electric current sintering (PECS). X-ray photoelectron spectroscopy (XPS) measurements revealed the presence of a nanometricWO3 layer on the EDM surface, confirming oxidation as the major material removal mechanism (MRM). The surface roughness after the final EDM finishing regime was strongly influenced by the composite homogeneity and could be reduced down to 0.15m(Ra) on agglomerate-free composites. Residual stress measurements indicated thatEDM did not introduce a significant amount of surface stresses, especially not after the final finishing regime. XRD measurements of EDM surfaces however indicated surface depletion of ZrO2 by the formation of ZrC andW2C during spark erosion.

Details

Original languageEnglish
Pages (from-to)114-120
JournalMaterials Chemistry and Physics
Volume123
Issue number1
DOIs
Publication statusPublished - Jun 2010

Keywords

  • Ceramics, electrical discharge machining, XPS, surface properties

ID: 132222