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2 papers
Lattice dynamics
Phase composition, microstructure, and electroconductivity of R$_{2}$O$_{3}$ solid electrolytes (R = Sc, Y, Ho, Er, Tm, Yb, Lu)
A. N. Meshcherskikhab,
A. A. Kolchuginab,
B. D. Antonova,
L. A. Dunyushkinaa a Institute of High-Temperature Electrochemistry, RAS, Yekaterinburg, Russia
b Ural Federal University named after the First President of Russia B. N. Yeltsin, Ekaterinburg
Abstract:
The effect of the addition of 11 mol.% R
$_{2}$O
$_{3}$ (R = Sc, Y, Ho, Er, Tm, Yb, Lu) on the phase and elemental composition, microstructure, and electrical conductivity of hafnium oxide was studied. When all additives, with the exception of scandium, are introduced into HfO
$_2$, solid solutions with a cubic structure such as fluorite are formed. The HfO
$_2$–Sc
$_{2}$O
$_{3}$ sample is an Hf
$_{7}$Sc
$_{2}$O
$_{17}$ phase having a fluorite-type lattice with rhombohedral distortions that undergoes reversible changes in the cubic structure at a temperature of
$\sim$ 760
$^{\circ}$C. It has been established that the nature of the dopant practically does not affect the microstructure of the HfO
$_2$–R
$_{2}$O
$_{3}$ ceramics; all samples are coarse-grained with a grain size of up to 10
$\mu$m. It was shown that the conductivity of HfO
$_2$–R
$_{2}$O
$_{3}$ samples is determined by the volume of grains. The most promising materials for use as a solid oxide electrolyte are HfO
$_2$–Tm
$_{2}$O
$_{3}$ and HfO
$_2$–Yb
$_{2}$O
$_{3}$, in which high conductivity is combined with structural stability.
Keywords:
hafnium oxide, solid oxide electrolyte, rare earth elements, electrical conductivity, thermal expansion, phase transition. Received: 23.07.2019
Revised: 23.07.2019
Accepted: 09.08.2019
DOI:
10.21883/FTT.2020.01.48752.557
Fulltext:
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