Electrical Discharge Machining of (NbxZr1-x)B2-SiC Composites

The interrelationships between microstructure, Electrical Discharge Machining (EDM) behavior and surface quality of stoichometrically mixed NbxZr1-xB2-SiC composites with x ranging from 0 to 1 with intervals of 0.25 have been investigated. The composites were fully densified by means of Pulsed Electric Current Sintering (PECS) and XRD measurements confirm full solubility of the two components. XPS measurements reveal the presence of respectively Nb2O5, ZrO2 or both at the EDM surface, which are responsible for a difference in material removal mechanisms (MRM) and surface quality. It is shown that the presence of transition metal oxides in the heat affected zone influence surface quality and material removal rate considerably.