Effect of TiO₂ Addition on Cutting Performance of Si₃N₄ Ceramic Cutting Tool

Si₃N₄ ceramic with mass fraction of 5% TiO₂ was prepared by gas pressure sintering and was made into a cutting tool. The effects of TiO₂ on its microstructure, mechanical properties and cutting performance were investigated, and compared with Si₃N₄ ceramic sintered without TiO₂. The results show that the sintered Si₃N₄ ceramic with TiO₂ was mainly composed of long rod-shaped and equiaxed β-Si₃N₄ grains, accompanied by uniformly distributed TiN phases. Compared with the sintered Si₃N₄ ceramic without TiO₂, the grains were refined, and the hardness increased while the fracture toughness decreased slightly. In the continuous cutting process of gray cast iron, Si₃N₄ ceramic cutting tool with TiO₂ had a longer cutting life (effective cutting length of 2 410 m) and maintained the integrity of the cutting edge, and had less adhesive wear debris after cutting.