Thermal and electrical properties of spark plasma sintered (Ti,Cr)B2 ceramics

Thermal and electrical properties were measured for TiB2 ceramics containing varying CrB2 contents up to 33 mol%. The room-temperature thermal diffusivity decreased with increasing Cr content from 0.330 +/- 0.003 cm(2)/s for pure TiB2 to 0.060 +/- 0.003 cm(2)/s for (Ti0.66Cr0.33)B-2. The amount of anisotropy in the coefficients of thermal expansion increased with increasing Cr content and the c-axis had the greatest dependence on Cr addition, with an increase of more than 25% in the thermal expansion for 33 mol% CrB2 compared to TiB2, whereas the a-axis only increased by about 8%. The electrical conductivity was the lowest for (Ti0.66Cr0.33)B-2 at similar to 8.5 x 10(3) S/cm compared to similar to 106.1 x 10(3) S/cm for nominally pure TiB2. Overall, the addition of CrB2 as a sintering aid for TiB2 was shown to have a significant effect on the thermal and electrical properties of TiB2 for additions as small as 5 mol% CrB2.