Highly porous multicomponent (Hf1/3Ta1/3Nb1/3)C ultra-high temperature ceramic with low thermal conductivity

Fundamental requirements of ultra-high temperature ceramic (UHTC) thermal insulators are excellent thermal stability above 1800 °C, good thermal insulation capability, and high mechanical reliability. We report foam-gelcasting-freeze drying method to fabricate porous multicomponent (Hf1/3Ta1/3Nb1/3)...

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Bibliographic Details
Published in:Materialia 2021-08, Vol.18, p.101158, Article 101158
Main Authors: Wu, Zhen, Liang, Xianpeng, Shao, Zhuojie, Chen, Haikun, Li, Junning, Wang, Jingyang
Format: Article
Language:English
Subjects:
High porosity
Low thermal conductivity
Multicomponent transition metal carbide
UHTC thermal insulator
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Summary:Fundamental requirements of ultra-high temperature ceramic (UHTC) thermal insulators are excellent thermal stability above 1800 °C, good thermal insulation capability, and high mechanical reliability. We report foam-gelcasting-freeze drying method to fabricate porous multicomponent (Hf1/3Ta1/3Nb1/3)C UHTC with superhigh porosity (90.0-94.0%). The as-prepared samples show low density (0.70–1.17 g/cm3), moderately high compressive strength (0.34–1.34 MPa), low thermal conductivity (0.089–0.098 W/(m•K)), and excellent ultra-high temperature stability (low shrinkage of < 1% after thermal cycles up to 2000 °C). Coordinative mechanisms of multicomponent induced phonon scattering enhancement and low solid skeleton thermal conduction are the main factors that provide excellent thermal insulation capability. [Display omitted]
ISSN:2589-1529
2589-1529
DOI:10.1016/j.mtla.2021.101158