Thermal and electrical properties of TiB2–MoSi2

Abstract

Abstract The present communication reports the effect of MoSi 2 addition on high temperature thermal conductivity and room temperature (RT) electrical properties of TiB 2 . The thermal diffusivity and the thermal conductivity of the hot pressed TiB 2 –MoSi 2 samples were measured over a range from room temperature to 1000 °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 TiB 2 samples exhibit linear dependence on temperature and the measured thermal conductivity of TiB 2 -2.5% MoSi 2 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 °C) and then decreases with further increasing temperature. It is interesting to note that both the thermal conductivity and electrical conductivity of TiB 2 samples enhanced with the addition of 2.5 wt.% MoSi 2 sinter additive. Among all the samples, TiB 2 -2.5 wt.% MoSi 2 ceramics measured with high thermal conductivity (77 W/mK) and low electrical resistivity (12 μΩ-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 TiB 2 were adversely affected with further increasing the amount of MoSi 2 (10 wt.%).