Preparation and thermal shock properties of Si3N4-WC nanocomposites

Si₃N₄-WC nanocomposites were fabricated by hot-pressing nano-sized Si₃N₄ powders and sub-micrometer WC powders. The effect of WC particles on mechanical properties and thermal shock properties of silicon nitride ceramics were analyzed and discussed. The addition of proper amount of WC particles can improve the flexural strength and the fracture toughness, the optimum amount was 8wt.% and 4wt.% respectively. Si₃N₄-WC nanocomposites showed both higher critical temperature difference and better resistance to crack propagation compared to those of the monolithic silicon nitride ceramic.