Thermophysical Properties of ZrB2-Based Ceramics

Abstract

Thermophysical peoperties were investigated for ZrB2 and ZrB2-30vol% SiC ceramics. Thermal conductivities were calculated from measured thermal diffusivities, heat capacities, and thermal expansions. The thermal conductivity of ZrB2 increased from 58.7 W/m K at room temperature to 62.0 W/m K at 1675 K, whereas the thermal conductivity of ZrB2-SiC decreased from 62.0 W/m K to 56 W/m K over the same temperature range. Electron and phonon contributions to thermal conductivity were determined using electrical resistivity measurements and were used, along with grain size models, to explain the observed trends. The results are compared to previously reported thermal conductivities for ZrB2 and ZrB2-SiC.