Microstructure and mechanical properties of TiN/Si3N4 nanocomposites by spark plasma sintering (SPS)

TiN/Si3N4 nanocomposites were fabricated from beta-Si3N4 and TiN nano powders by powder processing routes. The specimens were consolidated at 1600 degrees C for 3 min by spark plasma sintering, and nearly full densification was obtained in the resulting sintered bulk composites. The TiN phase grows rapidly and a typical twin structure of TiN can be observed in the composites. The grain size and distribution for TiN may affect the electrical resistivity, leading to a pulse current through the sintering compact. The resulting microstructure for the composite containing 10 wt% TiN reveals that grain coarsening behavior for beta-Si3N4 based grains is accelerated, and the composite has the highest toughness of 4.9 MPa m(1/2) among all these composites. The other composites show nanosized beta-Si3N4 based grains with a fracture toughness of nearly 4.2 MPa m(1/2). (c) 2010 Elsevier B.V. All rights reserved.