Development of ZrO2-WC composites by pulsed electric current sintering

ZrO2-WC ceramic composites with 40 vol% WC were consolidated by pulsed electric current sintering (PECS) for 4 min at 1450 degrees C under a pressure of 60 MPa. The effect of ZrO2 stabilizers and the source of WC powder on the densitication, phase constitution, microstructure and mechanical properties of the ZrO2-WC composites were investigated and analyzed. The experimental results revealed that the amount and type Of ZrO2 stabilizers played a primary role on the phase constitution and mechanical properties of the composites in comparison to the morphology and size of the WC powder. The 2 mol% Y2O3-stabilized composites exhibited much better mechanical properties than that of 1.75 mol% Y2O3-stabilized or I MOM Y2O3 + 6 or 8 mol% CeO2 co-stabilized composites. A Vickers hardness of 16.2 GPa, fracture toughness of 6.9 MPa m(1/2), and flexural strength of 1982 MPa were obtained for the composites PECS from a mixture of nanometer sized WC and 2 mol% Y2O3-stabilized ZrO2 powder. (C) 2006 Elsevier Ltd. All rights reserved.status: publishe