ZrO2-WC nanocomposites with superior properties

Fully dense ZrO2-based nanocomposites with 5-40vol.% WC were produced by hot pressing at 1450 degrees C for I h. The hardness and bending strength of the composites increases with increasing WC content, whereas the toughness hardly changes. An exceptionally high strength of 2 GPa combined with a hardness of 14.80 GPa and an excellent fracture toughness of 9.4 MPa m(1/2) was obtained for the 2 mol% Y2O3 stabilised ZrO(2-)based composite with 40 vol.% WC. Such an attractive combination of properties is quite unique for a ceramic composite and is only matched by WC-Co cermets. The composites are substantially harder and stronger than the fine-grained Y-TZP, whereas the excellent toughness of Y-TZP is maintained. The strength improvement was accompanied with a change in fracture mode of the ZrO2 grains from intergranular to transgranular. The ZrO2-WC nanocomposites were found to slightly plastically deform before fracturing during bending. (c) 2006 Elsevier Ltd. All rights reserved.