Effect of nano-TiN particles on microstructure and mechanical properties of Si 3 N 4 -based nanoceramics

Abstract

Effect of nano-TiN particles on the microstructure and mechanical properties of Si₃N₄ based cearmics were investigated. The nanocomposites were fabricated by hot pressing Si₃N₄ and TiN nanopowders. The main phases in nanocomposites were α-Si₃N₄, β-Si₃N₄, Si₂N₂O and TiN. Proper addition of TiN nanoparticles can significantly increase the flexural strength and the fracture toughness. The maximum values of the fracture toughness and the flexural strength were obtained when the content of TiN particles was 10 and 15 wt-% respectively. The hardness of the nanocomposite slightly decreased with the addition of nano-TiN particles. The main strengthening and toughening mechanisms are the crack tip bridging and the crack deflection by TiN particles.