Microstructure and Mechanical Properties of Spark Plasma Sintered Si3N4/WC Ceramic Tools

Silicon nitride (Si 3N 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 3N 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 3N 4-based ceramic materials were analyzed. Results showed that Si 3N 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 3N 4-based ceramic tool material is uniform without obvious abnormal growth. The Si 3N 4-based ceramic tool was mainly composed of α-Si 3N 4, β-Si 3N 4, and WC phases. View Full-Tex