Spark plasma sintering of TiC-SiCw ceramics

Abstract

Silicon carbide whiskers (SiCw) in TiC had impressive impacts on the properties and made it possible for special applications which generally would not be conceivable with TiC alone. In the present work, SiCw reinforced TiC based composites were prepared by spark plasma sintering (SPS) technique, at the temperature of 1900 degrees C under the pressure of 40 MPa for sintering time of 7 min. To test out the effects of different amount of SiC whisker (0, 10, 20 and 30 vol%) on the characteristics of TiC, the sintered samples were investigated about sinterability and physical-mechanical properties. Microstructure observations and density measurements confirmed that the composites were dense with uniformly distributed reinforcement, and the specimen doped with higher than 10 vol% SiCw could attain higher relative density (> 100%) than pure TiC and TiC-10 vol% SiCw. Also, the highest values for hardness (29.04 GPa) and thermal conductivity (39.2 W/mK) were achieved in specimen containing 30 vol% SiCw, whereas the optimum bending strength (644 MPa) was recorded in material containing 20 vol% SiCw. It seems that one of the reasons which contributes to this trend of properties variation is the generation of near-stoichiometric TiCx phase and new Ti3SiC2 compound.