Preparation and characterization of tantalum carbide (TaC) ceramics

• TaC without additives were consolidated within the range of 1350–1900 °C using SPS.
• Dense TaC ceramics (relative density > 98%) obtained above 1375 °C.
• Only the TaC phase was detected in the sintered bodies.
• Young's modulus for a fully dense TaC ceramic was estimated to be 558 GPa.
• The temperature dependence of the thermal conductivity exhibited metallic behavior.

Tantalum carbide (TaC) ceramics without sintering additives or transition metals were consolidated within a sintering temperature range of 1350–1900 °C using a resistance-heated hot-pressing technique. Dense TaC ceramics having relative density values above 98 vol.% were obtained at temperatures exceeding 1375 °C, and only the TaC phase with stoichiometric or closely stoichiometric compositions was detected in the sintered bodies. The average grain size of the TaC grains increased significantly with sintering temperature. Young's modulus for dense, pure TaC ceramics (relative density > 98 vol.%) ranged from 531 to 549 GPa; a fully dense TaC ceramic was estimated to have a Young's modulus value of 558 GPa. The hardness of the dense TaC ceramic was ~ 14 GPa, regardless of the TaC average grain size, and the fracture toughness was ~ 4 MPa m0.5. The electrical resistivity of the TaC ceramic was 0.36 μΩ m at 20 °C and increased linearly with temperature. The thermal conductivity of the TaC ceramic, 27.9 W (m K)− 1 at 25 °C, increased with temperature.