High-entropy fluorite oxides
High-entropy fluorite oxides
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DOI：
10.1016/j.jeurceramsoc.2018.04.010
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发表时间：
2018-08-01
影响因子：
5.7
通讯作者：
Luo, Jian
中科院分区：
文献类型：
--
作者：
Gild, Joshua;Samiee, Mojtaba;Luo, Jian
通过高能球磨、火花等离子烧结和空气退火制备了11种具有5个主阳离子（外加4个主阳离子（Hf0.25Zr0.25Ce0.25Y0.25） o2 - δ作为起始点和基准）的萤石氧化物。（Hf0.25Zr0.25Ce0.25 y0.25） o2 - δ、（Hf0.25Zr0.25Ce0.25）（Y0.125Yb0.125） o2 - δ、（Hf0.2Zr0.2Ce0.2）Y0.2Yb0.2) o2 - δ、（Hf0.25Zr0.25Ce0.25）（Y0.125Ca0.125） o2 - δ、（Hf0.25Zr0.25Ce0.25）（Y0.125Gd0.125） o2 - δ、（Hf0.2Zr0.2Ce0.2）（Y0.2Gd0.2） o2 - δ、（hf0.25 zr0.2 ce0.25）（Y0.2Gd0.2） o2 - δ、（hf0.2 zr0.2 ce0.25）（Y0.2Gd0.2） o2 - δ、（hf0.2 zr0.2 ce0.25）（y0.2 zr0.2 ce0.25）（Y0.2Gd0.2） o2 - δ、（Hf0.2Zr0.2Ce0.2）（yb0.2 zr0.2 ce0.2）（Yb0.2Gd0.2） o2 - δ、（Hf0.2Zr0.2Ce0.2）（yb0.2 ce0.2）（Yb0.2Gd0.2） o2 - δ和（Hf0.2Zr0.2Ce0.2）（Yb0.2Gd0.2） o2 - δ。具有萤石晶体结构的单相固溶体，具有高构型熵（在阳离子亚晶格上），类似于先前研究中报道的高熵合金和陶瓷。除了同时含有Yb和Gd的两种高熵萤石氧化物（hefo）外，大多数高熵萤石氧化物都可以烧结到较高的相对密度。与8mol . % Y2O3稳定的ZrO2 （8YSZ）相比，这些单相hefo具有较低的导电性和相当的硬度（即使含有较高的较软成分，如Y2O3和Yb2O3）。值得注意的是，这些单相hefo具有比8YSZ更低的热导率，可能是由于多个阳离子和应变晶格的高声子散射。
Eleven fluorite oxides with five principal cations (in addition to a four-principal-cation (Hf0.25Zr0.25Ce0.25Y0.25) O2-delta as a start point and baseline) were fabricated via high-energy ball milling, spark plasma sintering, and annealing in air. Eight of the compositions, namely (Hf0.25Zr0.25Ce0.25Y0.25)O2-delta, (Hf0.25Zr0.25Ce0.25) (Y0.125Yb0.125)O2-delta, (Hf0.2Zr0.2Ce0.2)Y0.2Yb0.2)O2-delta, (Hf0.25Zr0.25Ce0.25)(Y0.125Ca0.125)O2-delta, (Hf0.25Zr0.25Ce0.25) (Y0.125Gd0.125)O2-delta, (Hf0.2Zr0.2Ce0.2)(Y0.2Gd0.2)O2-delta, (Hf0.25Zr0.25Ce0.25)(Yb0.125Gd0.125)O2-delta, and (Hf0.2Zr0.2Ce0.2) (Yb0.2Gd0.2)O2-delta, possess single-phase solid solutions of the fluorite crystal structure with high configurational entropies (on the cation sublattices), akin to those high-entropy alloys and ceramics reported in prior studies. Most high-entropy fluorite oxides (HEFOs), except for the two containing both Yb and Gd, can be sintered to high relative densities. These single-phase HEFOs exhibit lower electrical conductivities and comparable hardness (even with higher contents of softer components such as Y2O3 and Yb2O3), in comparison with 8 mol. % Y2O3-stabilized ZrO2 (8YSZ). Notably, these single-phase HEFOs possess lower thermal conductivities than that of 8YSZ, presumably due to high phonon scattering by multiple cations and strained lattices.