Porous high-entropy (Zr0.25Hf0.25Nb0.25Ti0.25)C with high strength and uniform pore structure fabricated by freeze-casting

Ultra-high temperature ceramics (UHTCs) are considered as promising thermal insulation materials applied in ultra-high temperature environments (> 2000 °C). However, the high thermal conductivity and high density limit their further development and application. Herein we adopt the strategies of i...

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Bibliographic Details
Published in:Journal of materials science 2024-06, Vol.59 (22), p.9941-9951
Main Authors: Zeng, Dawei, Zhou, Jiaxin, Wu, Zhen, Sun, Luchao, Wang, Jingyang
Format: Article
Language:English
Subjects:
Ceramics
Characterization and Evaluation of Materials
Chemistry and Materials Science
Classical Mechanics
Compressive strength
Crystallography and Scattering Methods
Entropy
Heat conductivity
Heat transfer
High temperature
High temperature environments
Lightweight Materials
Materials Science
Materials selection
Polymer Sciences
Pore size
Porosity
Solid Mechanics
Thermal conductivity
Thermal insulation
Ultrahigh temperature
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Summary:Ultra-high temperature ceramics (UHTCs) are considered as promising thermal insulation materials applied in ultra-high temperature environments (> 2000 °C). However, the high thermal conductivity and high density limit their further development and application. Herein we adopt the strategies of introducing porous structure and high-entropy effect to solve the above problems. Thus porous high-entropy (Zr 0.25 Hf 0.25 Nb 0.25 Ti 0.25 )C ceramics were prepared. In order to obtain the uniform pore structure and high mechanical property, the camphene-based freeze-casting method was used in this study. The as-prepared porous samples exhibit high porosity of 92.01–73.57% and homogeneously interconnected pore structure with average pore size of 40.8–19.6 μm. Besides, this work realizes the aims of lightweight (0.65–2.15 g/cm 3 ) and low thermal conductivity (0.29–1.53 W/(m·K)). More importantly, porous samples still have the merit of high compressive strength (0.38–29.02 MPa) due to the even microstructure. The results show that highly porous high-entropy (Zr 0.25 Hf 0.25 Nb 0.25 Ti 0.25 )C with good overall properties can be an excellent candidate material for ultra-high temperature thermal insulation.
ISSN:0022-2461
1573-4803
DOI:10.1007/s10853-024-09456-0