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Effect of A-Site Nonstoichiometry on Defect Chemistry and Electrical Conductivity of Undoped and Y-Doped SrZrO(3)

The effect of Sr-nonstoichiometry on phase composition, microstructure, defect chemistry and electrical conductivity of Sr(x)ZrO(3−δ) and Sr(x)Zr(0.95)Y(0.05)O(3−δ) ceramics (SZx and SZYx, respectively; x = 0.94–1.02) was investigated via X-ray diffraction, scanning electron microscopy, energy-dispe...

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Autores principales: Dunyushkina, Liliya, Khaliullina, Adelya, Meshcherskikh, Anastasia, Pankratov, Alexander, Osinkin, Denis
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6514593/
https://www.ncbi.nlm.nih.gov/pubmed/30999578
http://dx.doi.org/10.3390/ma12081258
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author Dunyushkina, Liliya
Khaliullina, Adelya
Meshcherskikh, Anastasia
Pankratov, Alexander
Osinkin, Denis
author_facet Dunyushkina, Liliya
Khaliullina, Adelya
Meshcherskikh, Anastasia
Pankratov, Alexander
Osinkin, Denis
author_sort Dunyushkina, Liliya
collection PubMed
description The effect of Sr-nonstoichiometry on phase composition, microstructure, defect chemistry and electrical conductivity of Sr(x)ZrO(3−δ) and Sr(x)Zr(0.95)Y(0.05)O(3−δ) ceramics (SZx and SZYx, respectively; x = 0.94–1.02) was investigated via X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and impedance spectroscopy followed by distribution of relaxation times analysis of impedance data. It was shown that at low Sr deficiency (x > 0.96 and 0.98 for SZx and SZYx, respectively) a solid solution of strontium vacancies in strontium zirconate crystal structure forms, whereas at higher Sr deficiency the secondary phase, zirconium oxide or yttrium zirconium oxide, is precipitated. Yttrium solubility limit in strontium zirconate was found to be close to 2 mol%. Y-doped strontium zirconates possess up to two orders of magnitude higher total conductivity than SZx samples. A-site nonstoichiometry was shown to have a significant effect on the electrical conductivity of SZx and SZYx. The highest total and bulk conductivity were observed at x = 0.98 for both systems. Increasing the conductivity with a rise in humidity indicates that proton conduction appears in the oxides in wet conditions. A defect model based on consideration of different types of point defects, such as strontium vacancies, substitutional defects and oxygen vacancies, and assumption of Y ions partitioning over Zr and Sr sites was elaborated. The proposed model consistently describes the obtained data on conductivity.
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spelling pubmed-65145932019-05-31 Effect of A-Site Nonstoichiometry on Defect Chemistry and Electrical Conductivity of Undoped and Y-Doped SrZrO(3) Dunyushkina, Liliya Khaliullina, Adelya Meshcherskikh, Anastasia Pankratov, Alexander Osinkin, Denis Materials (Basel) Article The effect of Sr-nonstoichiometry on phase composition, microstructure, defect chemistry and electrical conductivity of Sr(x)ZrO(3−δ) and Sr(x)Zr(0.95)Y(0.05)O(3−δ) ceramics (SZx and SZYx, respectively; x = 0.94–1.02) was investigated via X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and impedance spectroscopy followed by distribution of relaxation times analysis of impedance data. It was shown that at low Sr deficiency (x > 0.96 and 0.98 for SZx and SZYx, respectively) a solid solution of strontium vacancies in strontium zirconate crystal structure forms, whereas at higher Sr deficiency the secondary phase, zirconium oxide or yttrium zirconium oxide, is precipitated. Yttrium solubility limit in strontium zirconate was found to be close to 2 mol%. Y-doped strontium zirconates possess up to two orders of magnitude higher total conductivity than SZx samples. A-site nonstoichiometry was shown to have a significant effect on the electrical conductivity of SZx and SZYx. The highest total and bulk conductivity were observed at x = 0.98 for both systems. Increasing the conductivity with a rise in humidity indicates that proton conduction appears in the oxides in wet conditions. A defect model based on consideration of different types of point defects, such as strontium vacancies, substitutional defects and oxygen vacancies, and assumption of Y ions partitioning over Zr and Sr sites was elaborated. The proposed model consistently describes the obtained data on conductivity. MDPI 2019-04-17 /pmc/articles/PMC6514593/ /pubmed/30999578 http://dx.doi.org/10.3390/ma12081258 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Dunyushkina, Liliya
Khaliullina, Adelya
Meshcherskikh, Anastasia
Pankratov, Alexander
Osinkin, Denis
Effect of A-Site Nonstoichiometry on Defect Chemistry and Electrical Conductivity of Undoped and Y-Doped SrZrO(3)
title Effect of A-Site Nonstoichiometry on Defect Chemistry and Electrical Conductivity of Undoped and Y-Doped SrZrO(3)
title_full Effect of A-Site Nonstoichiometry on Defect Chemistry and Electrical Conductivity of Undoped and Y-Doped SrZrO(3)
title_fullStr Effect of A-Site Nonstoichiometry on Defect Chemistry and Electrical Conductivity of Undoped and Y-Doped SrZrO(3)
title_full_unstemmed Effect of A-Site Nonstoichiometry on Defect Chemistry and Electrical Conductivity of Undoped and Y-Doped SrZrO(3)
title_short Effect of A-Site Nonstoichiometry on Defect Chemistry and Electrical Conductivity of Undoped and Y-Doped SrZrO(3)
title_sort effect of a-site nonstoichiometry on defect chemistry and electrical conductivity of undoped and y-doped srzro(3)
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6514593/
https://www.ncbi.nlm.nih.gov/pubmed/30999578
http://dx.doi.org/10.3390/ma12081258
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