Composition design and preparation of rare-earth-free high-entropy fluorite oxides

IF 5.8 2区材料科学 Q1 MATERIALS SCIENCE, CERAMICS

Journal of The European Ceramic Society Pub Date : 2025-04-27 DOI:10.1016/j.jeurceramsoc.2025.117486

Guangjin Chen , Cuiwei Li , Yuwei Zhang , Chenran Zhao , Tianyu Liu , Kepi Chen

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引用次数: 0

Abstract

High-entropy fluorite oxides (HEFOs) demonstrate a broader application prospect as thermal insulators due to their outstanding properties. Currently, the synthesized HEFOs contain at least one type of rare earth elements (REEs), which are listed as critical materials by some international institutions. To explore the possibility of rare-earth-free HEFOs, first-principals calculations and the solid state reaction method were employed by adjusting the mean cation radius (

\overset{̅}{r}

) and oxygen vacancy concentration (O_vac) of (Ca,Zr,Hf,Sn,Ti)O_2-δ. The first-principles calculations results indicate that the Gibbs free energy change (ΔG(T)) could be controlled by adjusting

\overset{̅}{r}

and O_vac, and the ΔG(T) of (Ca_0.2Zr_0.2Hf_0.2Sn_0.2Ti_0.2)O_2-δ was slightly higher than zero. After further detailed composition design, a novel rare-earth-free HEFOs composed of (Ca_0.2Zr_0.28Hf_0.28Sn_0.19Ti_0.05)O_2-δ with a higher

\overset{̅}{r}

has been successfully synthesized for the first time. Its thermal conductivity is 1.22 W·m⁻¹·K⁻¹, which is much lower than that of most HEFOs mainly composed of REEs.

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无稀土高熵萤石氧化物的组成设计与制备

高熵萤石氧化物（HEFOs）由于其优异的性能，作为绝缘体具有广阔的应用前景。目前，合成的hefo至少含有一种被一些国际机构列为关键材料的稀土元素（ree）。为了探索无稀土hefo的可能性，通过调整（Ca,Zr,Hf,Sn,Ti）O2-δ的平均阳离子半径（r′s）和氧空位浓度（Ovac），采用第一主元计算和固相反应方法。第一原理计算结果表明，可以通过调节r′s和Ovac来控制吉布斯自由能变化ΔG(T)，且（Ca0.2Zr0.2Hf0.2Sn0.2Ti0.2）O2-δ的ΔG(T)略大于零。经过进一步的详细组成设计，首次成功合成了具有较高r′s的（Ca0.2Zr0.28Hf0.28Sn0.19Ti0.05）O2-δ的新型无稀土hefo。其导热系数为1.22 W·m−1·K−1，远低于以稀土元素为主的hefo。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of The European Ceramic Society 工程技术-材料科学：硅酸盐

CiteScore

10.70

自引率

12.30%

发文量

863

审稿时长

35 days

期刊介绍： The Journal of the European Ceramic Society publishes the results of original research and reviews relating to ceramic materials. Papers of either an experimental or theoretical character will be welcomed on a fully international basis. The emphasis is on novel generic science concerning the relationships between processing, microstructure and properties of polycrystalline ceramics consolidated at high temperature. Papers may relate to any of the conventional categories of ceramic: structural, functional, traditional or composite. The central objective is to sustain a high standard of research quality by means of appropriate reviewing procedures.