Microstructure and Mechanical Properties of Spark Plasma Sintered Si(3)N(4)/WC Ceramic Tools

Silicon nitride (Si(3)N(4)) based ceramic tools exhibit good machinability in cutting materials such as gray cast iron, ductile iron, malleable cast iron, and superalloys due to excellent high-temperature mechanical properties. In this paper, high-performance Si(3)N(4)-based ceramic tools containing tungsten carbide (WC) and cobalt (Co) were studied. Effects of the WC content and Co content on mechanical properties and a microstructure of Si(3)N(4)-based ceramic materials were analyzed. Results showed that Si(3)N(4)-based ceramic material containing 10 wt % WC and 1 wt % Co had the best comprehensive mechanical properties at a sintering temperature of 1650 °C and holding time of 6 min, achieving Vickers hardness, fracture toughness, and room temperature bending strength of 16.96 GPa, 7.26 MPa·m(1/2), and 1132 MPa, respectively. The microstructure of Si(3)N(4)-based ceramic tool material is uniform without obvious abnormal growth. The Si(3)N(4)-based ceramic tool was mainly composed of α-Si(3)N(4), β-Si(3)N(4), and WC phases.