Reactive Hot Pressing of ZrC-SiC Ceramics at Low Temperature

Composites of ZrCSiC with relative densities in excess of 98% were prepared by reactive hot pressing of ZrC and Si at temperature as low as 1600 degrees C. The reaction between ZrC and Si resulted in the formation of ZrC1-x, SiC, and ZrSi. Low-temperature densification of ZrC-SiC ceramics is attributed to the formed nonstoichiometric ZrC1-x and ZrSi liquid phase. Adding 5 wt% Si to ZrC, the three-point bending strength of formed ZrC0.813.4 vol%SiC ceramics reached 819 +/- 102 MPa with hardness and toughness being 20.5 GPa and 3.3 MPa.m1/2, respectively.