Effect of BN Addition on the Mechanical Properties of TiN-BN Composites

Titanium nitride (TiN) has been used extensively in coating materials and cutting tools because of its attractive properties, which include low density, high melting point, high hardness and thermodynamic stability. However, like many ceramic materials, its low fracture toughness limits wide industrial application. The methods generally utilized to improve its fracture toughness involve the fabrication of nanostructured materials and composites. In this paper, BN was evaluated as a reinforcing material in TiN ceramics by pulsed current activated sintering method. Highly dense nanostructured TiN and TiN-BN composites were achieved within 1 min at 1400 degrees C. The effect of BN on the grain size, hardness and fracture toughness of TiN BN composites was evaluated. The addition of BN to TiN simultaneously improved the hardness and fracture toughness of the TiN-BN composite by refining TiN and the deterrence of crack propagation by BN.