Electrically conductive silicon carbide with the addition of Ti-NbC

The work deals with the preparation of dense SiC based ceramics with high electrical conductivity. SiC samples with different content of conductive Ti-Nb-Si-C-O based phase were hot pressed at 1820 degrees C for 1 h in Ar atmosphere under mechanical pressure of 30 MPa. The conductive phase is a mixture of 50 wt% Ti-NbC (molar ratio of Ti/NbC is 1:1.8) and 50 wt% eutectic composition of Y2O3-SiO2. Composite with 30% of conductive Ti-Nb-Si-C-O phase showed the highest electrical conductivity 28.4 S mm(-1), while the good mechanical properties of SiC matrix were preserved (fracture toughness K-IC = 5.4 MPa m(1/2) and Vickers hardness 17.8 GPa). The obtained results show that the developed additive system is suitable for the preparation of SiC-based composite with sufficient electrical conductivity for electric discharge machining. (C) 2012 Elsevier Ltd. All rights reserved.