High-entropy fluorite oxides

By Joshua Gild, M. Samiee, Jeffrey L. Braun, Tyler J. Harrington, Heidy Vega, P. Hopkins, Kenneth S. Vecchio, Jian Luo. Journal of the European Ceramic Society, 2018

535 citations recorded by the source corpus.

Abstract Eleven fluorite oxides with five principal cations (in addition to a four-principal-cation (Hf0.25Zr0.25Ce0.25Y0.25)O2-δ 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-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, (Hf0.25Zr0.25Ce0.25)(Yb0.125Gd0.125)O2-δ, and (Hf0.2Zr0.2Ce0.2)(Yb0.2Gd0.2)O2-δ, 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.

Subfields: Aerospace Engineering, Geophysics, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/d2a718b62ef5cfcbc4b7b5a6b01ade915dc9d1d3

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Aerospace Engineering

1. Jian Luo
2. E. Opila
3. P. Hopkins
4. Qingyang Wang
5. Hanzhu Zhang
6. Tyler J. Harrington
7. Farid Akhtar
8. Andrew J. Wright

In Geophysics

1. Renkun Chen

In Mechanical Engineering

1. Jian Luo
2. Andrew J. Wright
3. Joshua Gild
4. E. Opila
5. P. Hopkins
6. A. Nieto
7. Tyler J. Harrington
8. Farid Akhtar

Citations in the corpus

• Thermal conductivity and hardness of three single-phase high-entropy metal diborides fabricated by borocarbothermal reduction and spark plasma sintering (2020, background): “Since 2015, the field has expanded to include various high-entropy ceramics that have been fabricated in the bulk form, including high-entropy metal diborides [4,5], carbides [6–8], nitrides [9,10], sulfides [11], silicides [12,13], as well as fluorite [14,15], spinel [16,17], rocksalt [18], magneto”
• High-Entropy Ceramics (2019, methodology): “[14] fabricated high-entropy fluorite oxides from five fluorite oxides via high-energy ball milling and SPS, followed by various annealing treatments.”
• From high-entropy ceramics to compositionally-complex ceramics: A case study of fluorite oxides (2019, methodology): “2)O2, with equimolar HfO2-ZrO2-CeO2 as the matrix plus one or two stabilizers (selected from Y2O3, Yb2O3, Gd2O3, and CaO) [9].”