Thermal and electrical properties of TiB2-MoSi2

The present communication reports the effect of MoSi2 addition on high temperature thermal conductivity and room temperature (RT) electrical properties of TiB2. The thermal diffusivity and the thermal conductivity of the hot pressed TiB2-MoSi2 samples were measured over a range from room temperature to 1000 degrees C using the laser-flash technique, while electrical resistivity was measured at RT using a four linear probe method. The reciprocal of thermal diffusivity of TiB2 samples exhibit linear dependence on temperature and the measured thermal conductivity of TiB2-2.5% MoSi2 composites correlate well with the theoretical predictions from Hashin's model and Hasselman and Johnson's model. A common observation is that the thermal conductivity of all the samples slightly increases with temperature (up to 200 degrees C) and then decreases with further increasing temperature. It is interesting to note that both the thermal conductivity and electrical conductivity of TiB2 samples enhanced with the addition of 2.5 wt.% MoSi2 sinter additive. Among all the samples, TiB2-2.5 wt.% MoSi2 ceramics measured with high thermal conductivity (77 W/mK) and low electrical resistivity (12 mu Omega-cm) at room temperature. Such an improvement in properties can be attributed to its high density and low volume fraction of porosity. On the other hand, both the thermal and electrical properties of TiB2 Were adversely affected with further increasing the amount Of MoSi2 (10 wt-%). (C) 2009 Elsevier Ltd. All rights reserved.