Densification behavior and mechanical properties of the spark plasma sintered monolithic TiB2 ceramics

Monolithic TiB2 ceramics with fine-grained microstructures and good mechanical properties were synthesized by spark plasma sintering (SPS) technique under a pressure of 50 MPa, with heating rate of 150 degrees C/min, and sintering temperature ranging from 1200 degrees C to 1800 degrees C. Microstructures, mechanical properties, and densification behavior of the ceramics were investigated. Results indicate that TiB2 ceramics sintered at 1800 degrees C provide the optimal combination of dense microstructure and excellent properties, including the relative density of 97.6%, the microhardness of 29.6 +/- 2.5 GPa, the flexural strength of 538 +/- 45 MPa, and the fracture toughness of 5.2 +/- 0.4 MPa m(1/2). The dense microstructure is the main factor to improve the mechanical properties of the TiB2 ceramics synthesized by SPS process. (C) 2010 Elsevier B.V. All rights reserved.