Impact of Praseodymia Additions and Firing Conditions on Structural and Electrical Transport Properties of 5 mol.% Yttria Partially Stabilized Zirconia (5YSZ)
Ceramics samples with the nominal composition [(ZrO<sub>2</sub>)<sub>0.95</sub>(Y<sub>2</sub>O<sub>3</sub>)<sub>0.05</sub>]<sub>1-<i>x</i></sub>[PrO<i><sub>y</sub></i>]<i><sub>x<...
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doaj-53c7f18efd034629beb9592229f0859f2021-07-15T15:29:59ZengMDPI AGApplied Sciences2076-34172021-06-01115939593910.3390/app11135939Impact of Praseodymia Additions and Firing Conditions on Structural and Electrical Transport Properties of 5 mol.% Yttria Partially Stabilized Zirconia (5YSZ)Alejandro Natoli0Jorge R. Frade1Aleksandr Bamburov2Agnieszka Żurawska3Aleksey Yaremchenko4CICECO—Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, PortugalCICECO—Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, PortugalCICECO—Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, PortugalInstitute of Power Engineering—Research Institute, Mory 8 St., 01-330 Warsaw, PolandCICECO—Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, PortugalCeramics samples with the nominal composition [(ZrO<sub>2</sub>)<sub>0.95</sub>(Y<sub>2</sub>O<sub>3</sub>)<sub>0.05</sub>]<sub>1-<i>x</i></sub>[PrO<i><sub>y</sub></i>]<i><sub>x</sub></i> and praseodymia contents of <i>x</i> = 0.05–0.15 were prepared by the direct firing of compacted 5YSZ + PrO<i><sub>y</sub></i> mixtures at 1450–1550 °C for 1–9 h and characterized for prospective applicability in reversible solid oxide cells. XRD and SEM/EDS analysis revealed that the dissolution of praseodymium oxide in 5YSZ occurs via the formation of pyrochlore-type Pr<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> intermediate. Increasing PrO<i><sub>y</sub></i> additions results in a larger fraction of low-conducting pyrochlore phase and larger porosity, which limit the total electrical conductivity to 2.0–4.6 S/m at 900 °C and 0.28–0.68 S/m at 700 °C in air. A longer time and higher temperature of firing promotes the phase and microstructural homogenization of the ceramics but with comparatively low effect on density and conductivity. High-temperature processing leads to the prevailing 3+ oxidation state of praseodymium cations in fluorite and pyrochlore structures. The fraction of Pr<sup>4+</sup> at 600–1000 °C in air is ≤2% and is nearly independent of temperature. 5YSZ ceramics with praseodymia additions remain predominantly oxygen ionic conductors, with <i>p</i>-type electronic contribution increasing with Pr content but not exceeding 2% for <i>x</i> = 0.15 at 700–900 °C. The average thermal expansion coefficients of prepared ceramics are in the range of 10.4–10.7 ppm/K.https://www.mdpi.com/2076-3417/11/13/5939solid electrolyteyttria-stabilized zirconiapraseodymium oxideelectrical conductivityionic conductivitythermal expansion |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Alejandro Natoli Jorge R. Frade Aleksandr Bamburov Agnieszka Żurawska Aleksey Yaremchenko |
spellingShingle |
Alejandro Natoli Jorge R. Frade Aleksandr Bamburov Agnieszka Żurawska Aleksey Yaremchenko Impact of Praseodymia Additions and Firing Conditions on Structural and Electrical Transport Properties of 5 mol.% Yttria Partially Stabilized Zirconia (5YSZ) Applied Sciences solid electrolyte yttria-stabilized zirconia praseodymium oxide electrical conductivity ionic conductivity thermal expansion |
author_facet |
Alejandro Natoli Jorge R. Frade Aleksandr Bamburov Agnieszka Żurawska Aleksey Yaremchenko |
author_sort |
Alejandro Natoli |
title |
Impact of Praseodymia Additions and Firing Conditions on Structural and Electrical Transport Properties of 5 mol.% Yttria Partially Stabilized Zirconia (5YSZ) |
title_short |
Impact of Praseodymia Additions and Firing Conditions on Structural and Electrical Transport Properties of 5 mol.% Yttria Partially Stabilized Zirconia (5YSZ) |
title_full |
Impact of Praseodymia Additions and Firing Conditions on Structural and Electrical Transport Properties of 5 mol.% Yttria Partially Stabilized Zirconia (5YSZ) |
title_fullStr |
Impact of Praseodymia Additions and Firing Conditions on Structural and Electrical Transport Properties of 5 mol.% Yttria Partially Stabilized Zirconia (5YSZ) |
title_full_unstemmed |
Impact of Praseodymia Additions and Firing Conditions on Structural and Electrical Transport Properties of 5 mol.% Yttria Partially Stabilized Zirconia (5YSZ) |
title_sort |
impact of praseodymia additions and firing conditions on structural and electrical transport properties of 5 mol.% yttria partially stabilized zirconia (5ysz) |
publisher |
MDPI AG |
series |
Applied Sciences |
issn |
2076-3417 |
publishDate |
2021-06-01 |
description |
Ceramics samples with the nominal composition [(ZrO<sub>2</sub>)<sub>0.95</sub>(Y<sub>2</sub>O<sub>3</sub>)<sub>0.05</sub>]<sub>1-<i>x</i></sub>[PrO<i><sub>y</sub></i>]<i><sub>x</sub></i> and praseodymia contents of <i>x</i> = 0.05–0.15 were prepared by the direct firing of compacted 5YSZ + PrO<i><sub>y</sub></i> mixtures at 1450–1550 °C for 1–9 h and characterized for prospective applicability in reversible solid oxide cells. XRD and SEM/EDS analysis revealed that the dissolution of praseodymium oxide in 5YSZ occurs via the formation of pyrochlore-type Pr<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> intermediate. Increasing PrO<i><sub>y</sub></i> additions results in a larger fraction of low-conducting pyrochlore phase and larger porosity, which limit the total electrical conductivity to 2.0–4.6 S/m at 900 °C and 0.28–0.68 S/m at 700 °C in air. A longer time and higher temperature of firing promotes the phase and microstructural homogenization of the ceramics but with comparatively low effect on density and conductivity. High-temperature processing leads to the prevailing 3+ oxidation state of praseodymium cations in fluorite and pyrochlore structures. The fraction of Pr<sup>4+</sup> at 600–1000 °C in air is ≤2% and is nearly independent of temperature. 5YSZ ceramics with praseodymia additions remain predominantly oxygen ionic conductors, with <i>p</i>-type electronic contribution increasing with Pr content but not exceeding 2% for <i>x</i> = 0.15 at 700–900 °C. The average thermal expansion coefficients of prepared ceramics are in the range of 10.4–10.7 ppm/K. |
topic |
solid electrolyte yttria-stabilized zirconia praseodymium oxide electrical conductivity ionic conductivity thermal expansion |
url |
https://www.mdpi.com/2076-3417/11/13/5939 |
work_keys_str_mv |
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