Thermal and Electrical Properties of a High Entropy Carbide (Ta, Hf, Nb, Zr) at Elevated Temperatures

Abstract

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 cm2/s) and heat capacity (0.23-0.44 J/g·K) were measured from room temperature up to 2000°C. The thermal conductivity increased from 10.7 W/m·K at room temperature to 39.9 W/m·K at 2000°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 μΩ·cm at room temperature to 114.1 μΩ·cm at 800°C.

Department(s)

Materials Science and Engineering

Publication Status

Early View: Online Version of Record before inclusion in an issue

Comments

This research was conducted as part of the Enabling Materials for Extreme Environments Signature Area at Missouri University of Science and Technology. The authors also acknowledge the use of the Advanced Materials Characterization Laboratory at Missouri S&T. The research was supported by the EPSRC Programme Grant XMAT (EP/K008749/2).

Keywords and Phrases

Electrical Properties; Thermal Properties; Ultra-High Temperature Ceramics

International Standard Serial Number (ISSN)

1551-2916; 0002-7820

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2022 American Ceramic Society, All rights reserved.

Publication Date

15 Feb 2022

Link to Full Text

Share

 
COinS