Spark plasma sintering and growth kinetics of WC–ZrO2 ceramic matrix composites

WC–ZrO 2 ceramic matrix composites were fabricated via spark plasma sintering (SPS), and the effects of SPS on the microstructure, properties and grain growth kinetics of the composites were investigated. The phase compositions, morphologies and particle sizes of all samples were studied using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results showed that the optimal SPS parameters were 1650 °C, 5 min and 40 MPa. WC–10 wt.%ZrO 2 possessed optimal comprehensive properties with a relative density, hardness, and fracture toughness of 99.9%, HV 2003, and 11.3 MPa·m 1/2 , respectively. The values of the growth kinetics index and growth activation energy for WC–10wt.%ZrO 2 in the long-axis and short-axis directions were approximately 2.173 and 421.342 kJ/mol, and 2.326 and 457.685 kJ/mol, respectively. The growth mass transfer mechanisms of WC ceramic and WC–ZrO 2 ceramic matrix composites were controlled respectively by ion random diffusion and grain boundary diffusion.