Thermal and electrical properties of a high entropy carbide (Ta, Hf, Nb, Zr) at elevated temperatures

The thermal and electrical properties were measured for a high entropy carbide ceramic, consisting of (Hf, Ta, Zr, Nb)C. The ceramic was produced by spark plasma sintering a mixture of the monocarbides and had a relative density of more than 97.6%. The resulting ceramic was chemically homogeneous as a single-phase solid solution formed from the constituent carbides. The thermal diffusivity (0.045-0.087 cm(2)/s) and heat capacity (0.23-0.44 J/g center dot K) were measured from room temperature up to 2000 degrees C. The thermal conductivity increased from 10.7 W/m center dot K at room temperature to 39.9 W/m center dot K at 2000 degrees C. The phonon and electron contributions to the thermal conductivity were investigated, which showed that the increase in thermal conductivity was predominantly due to the electron contribution, while the phonon contribution was independent of temperature. The electrical resistivity increased from 80.9 mu omega center dot cm at room temperature to 114.1 mu omega center dot cm at 800 degrees C.

Automated summary

The thermal and electrical properties of a high entropy carbide ceramic, (Hf, Ta, Zr, Nb)C, were measured. The ceramic was produced through spark plasma sintering and showed chemically homogeneous composition. The results revealed high thermal conductivity primarily due to electron contributions.