@article{CHEN2023, 
author = {Lei CHEN and Wen ZHANG and Wenyu LU and Boxin WEI and Sijia HUO and Yujin WANG and Yu ZHOU},
title = {Low thermal conductivity of dense (TiZrHfVNbTa)Cx high-entropy carbides by tailoring carbon stoichiometry},
year = {2023},
journal = {Journal of Advanced Ceramics},
volume = {12},
number = {1},
pages = {49-58},
keywords = {thermal conductivity, high-entropy carbides, compositional complexity, carbon vacancies},
url = {https://www.sciopen.com/article/10.26599/JAC.2023.9220665},
doi = {10.26599/JAC.2023.9220665},
abstract = {Transition metal carbides are promising candidates for thermal protection materials due to their high melting points and excellent mechanical properties. However, the relatively high thermal conductivity is still a major obstacle to its application in an ultra-high-temperature insulation system. In this work, the low thermal conductivity of dense (TiZrHfVNbTa)Cx (x = 0.6–1) high-entropy carbides has been realized by adjusting the carbon stoichiometry. The thermal conductivity gradually decreases from 10.6 W·m−1·K−1 at room temperature to 6.4 W·m−1·K−1 with carbon vacancies increasing. Due to enhanced scattering of phonons and electrons by the carbon vacancies, nearly full-dense (97.9%) (TiZrHfVNbTa)C0.6 possesses low thermal conductivity of 6.4 W·m−1·K−1, thermal diffusivity of 2.3 mm2·s−1, as well as electrical resistivity of 165.5 μΩ·cm. The thermal conductivity of (TiZrHfVNbTa)C0.6 is lower than that of other quaternary and quinary high-entropy carbide ceramics, even if taking the difference of porosity into account in some cases, which is mainly attributed to compositional complexity and carbon vacancies. This provides a promising route to reduce the thermal conductivity of high-entropy carbides by increasing the number of metallic elements and carbon vacancies.}
}