Thermal and electrical properties of spark plasma sintered (Ti,Cr)B ₂ ceramics

Abstract

Abstract Thermal and electrical properties were measured for TiB 2 ceramics containing varying CrB 2 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 TiB 2 to 0.060 ± 0.003 cm 2 /s for (Ti 0.66 Cr 0.33 )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% CrB 2 compared to TiB 2 , whereas the a ‐axis only increased by about 8%. The electrical conductivity was the lowest for (Ti 0.66 Cr 0.33 )B 2 at ∼8.5 × 10 3 S/cm compared to ∼106.1 × 10 3 S/cm for nominally pure TiB 2 . Overall, the addition of CrB 2 as a sintering aid for TiB 2 was shown to have a significant effect on the thermal and electrical properties of TiB 2 for additions as small as 5 mol% CrB 2 .