Development of ZrO 2–WC composites by pulsed electric current sintering

Abstract

ZrO 2–WC ceramic composites with 40 vol% WC were consolidated by pulsed electric current sintering (PECS) for 4 min at 1450 °C under a pressure of 60 MPa. The effect of ZrO 2 stabilizers and the source of WC powder on the densification, phase constitution, microstructure and mechanical properties of the ZrO 2–WC composites were investigated and analyzed. The experimental results revealed that the amount and type of ZrO 2 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% Y 2O 3-stabilized composites exhibited much better mechanical properties than that of 1.75 mol% Y 2O 3-stabilized or 1 mol% Y 2O 3 + 6 or 8 mol% CeO 2 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% Y 2O 3-stabilized ZrO 2 powder.