Rare-Earth-Zirconate Porous High-Entropy Ceramics with Unique Pore Structures for Thermal Insulating Applications

Hengchang Wang; Jie Xu; Jiatong Zhu; Xuanyu Meng; Lang Lin; Ping Zhang; Feng Gao

doi:10.3390/ma16083040

Rare-Earth-Zirconate Porous High-Entropy Ceramics with Unique Pore Structures for Thermal Insulating Applications

Materials (Basel). 2023 Apr 12;16(8):3040. doi: 10.3390/ma16083040.

Authors

Hengchang Wang¹, Jie Xu^{1

2}, Jiatong Zhu¹, Xuanyu Meng¹, Lang Lin¹, Ping Zhang¹, Feng Gao^{1

2}

Affiliations

¹ MIIT Key Laboratory of Radiation Detection Materials and Devices, State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China.
² NPU-QMUL Joint Research Institute of Advanced Materials and Structure, Northwestern Polytechnical University, Xi'an 710072, China.

Abstract

Porous high-entropy ceramics are a new alternative material for thermal insulation. Their better stability and low thermal conductivity are due to lattice distortion and unique pore structures. In this work, rare-earth-zirconate ((La_0.25Eu_0.25Gd_0.25Yb_0.25)₂(Zr_0.75Ce_0.25)₂O₇) porous high-entropy ceramics were fabricated by a tert-butyl alcohol (TBA)-based gel-casting method. The regulation of pore structures was realized through changing different initial solid loadings. The XRD, HRTEM, and SAED results showed that the porous high-entropy ceramics had a single fluorite phase without impurity phases, exhibiting high porosity (67.1-81.5%), relatively high compressive strength (1.02-6.45 MPa) and low thermal conductivity (0.0642-0.1213 W/(m·K)) at room temperature. Porous high-entropy ceramics with 81.5% porosity demonstrated excellent thermal properties, showing a thermal conductivity of 0.0642 W/(m·K) at room temperature and 0.1467 W/(m·K) at 1200 °C. The unique pore structure with a micron size contributed to their excellent thermal insulating performance. The present work provides the prospect that rare-earth-zirconate porous high-entropy ceramics with tailored pore structures are expected to be thermal insulation materials.

Keywords: gel-casting; porous high-entropy ceramics; rare-earth-zirconate; thermal conductivity.

Grants and funding

This work was supported by the National Natural Science Foundation of China (No. 52072301, 51908551, 52272123), State Key Laboratory of New Ceramics and Fine Processing Tsinghua University (No. KFZD202102), Guangxi Science and Technology Plan Project (Gui Ke AB22035043), State Key Laboratory of Materials Processing and Die and Mold Technology, Huazhong University of Science and Technology (No. P2023-003), the International Cooperation Foundation of Shaanxi Province, China (No. 2022KW-34) and the Fundamental Research Funds for the Central Universities (No. D5000210722).