Electrical discharge machining of ZrO2 toughened WC composites

The interrelationships between the dispersion of the ZrO2 phase and the Electrical Discharge Machining (EDM) behaviour of WC-based composites with up to 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). XPS measurements reveal the presence of a nanometric WO3 layer on the EDM surface, confirming oxidation as a major material removal mechanism (MRM). The surface roughness after the final EDM finishing regime was strongly influenced by the presence of ZrO2 agglomerates and could be reduced down to 0.15 μm (Ra) on agglomerate-free composites.status: publishe