Grain-size dependence of the deterioration of oxygen transport for pure and 3 mol% Zr-doped Ba0.5Sr0.5Co0.8Fe0.2O3-δ induced by thermal annealing

Saim Saher, Matthias Meffert, Heike Störmer, Dagmar Gerthsen, Henny J.M. Bouwmeester

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Abstract

In this study, the influence of long-term annealing at intermediate temperatures on oxygen transport of Ba0.5Sr0.5Co0.8Fe0.2O3 d (BSCF) and 3 mol% Zr-doped BSCF (BSCF-Z3) ceramics with different grain sizes was studied by means of in situ electrical conductivity relaxation (ECR) measurements. Ceramics with different grain sizes in the range of 3–80 mm were obtained by varying the temperature and dwell time during sintering. For both compositions, the apparent values of the chemical diffusion coefficient Dchem and surface exchange coefficient kchem extracted from the data of ECR measurements are found to decrease with the time of annealing. The strongly correlated decreases in Dchem and kchem, being greater in magnitude at a lower grain size and temperature, are observed significantly more pronounced for BSCF than for BSCF-Z3. The results from microstructural analysis provide a clear rationale for the observations from ECR. High-resolution transmission electron microscopy (TEM) images recorded before and after annealing under pure oxygen at 700 C for 13 d show excessive formation of hexagonal and plate-like lamellar precipitates at the grain boundaries and in the interior of grains of BSCF ceramics during the annealing process, whilst secondary phase formation is restricted solely to the grain boundary regions in BSCF-Z3. The possible importance of grain boundaries in determining the oxygen surface exchange kinetics is emphasized.
Original languageEnglish
Pages (from-to)4982-4990
JournalJournal of materials chemistry. A
Volume5
Issue number10
DOIs
Publication statusPublished - 2017

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Deterioration
Annealing
Oxygen
Grain boundaries
High resolution transmission electron microscopy
Temperature
Precipitates
Sintering
Kinetics
Hot Temperature
Chemical analysis
Electric Conductivity

Cite this

@article{c355015b63a04d159b1db55b5fd6a5de,
title = "Grain-size dependence of the deterioration of oxygen transport for pure and 3 mol{\%} Zr-doped Ba0.5Sr0.5Co0.8Fe0.2O3-δ induced by thermal annealing",
abstract = "In this study, the influence of long-term annealing at intermediate temperatures on oxygen transport of Ba0.5Sr0.5Co0.8Fe0.2O3 d (BSCF) and 3 mol{\%} Zr-doped BSCF (BSCF-Z3) ceramics with different grain sizes was studied by means of in situ electrical conductivity relaxation (ECR) measurements. Ceramics with different grain sizes in the range of 3–80 mm were obtained by varying the temperature and dwell time during sintering. For both compositions, the apparent values of the chemical diffusion coefficient Dchem and surface exchange coefficient kchem extracted from the data of ECR measurements are found to decrease with the time of annealing. The strongly correlated decreases in Dchem and kchem, being greater in magnitude at a lower grain size and temperature, are observed significantly more pronounced for BSCF than for BSCF-Z3. The results from microstructural analysis provide a clear rationale for the observations from ECR. High-resolution transmission electron microscopy (TEM) images recorded before and after annealing under pure oxygen at 700 C for 13 d show excessive formation of hexagonal and plate-like lamellar precipitates at the grain boundaries and in the interior of grains of BSCF ceramics during the annealing process, whilst secondary phase formation is restricted solely to the grain boundary regions in BSCF-Z3. The possible importance of grain boundaries in determining the oxygen surface exchange kinetics is emphasized.",
author = "Saim Saher and Matthias Meffert and Heike St{\"o}rmer and Dagmar Gerthsen and Bouwmeester, {Henny J.M.}",
year = "2017",
doi = "10.1039/c6ta10454a",
language = "English",
volume = "5",
pages = "4982--4990",
journal = "Journal of materials chemistry. A",
issn = "2050-7488",
publisher = "Royal Society of Chemistry",
number = "10",

}

Grain-size dependence of the deterioration of oxygen transport for pure and 3 mol% Zr-doped Ba0.5Sr0.5Co0.8Fe0.2O3-δ induced by thermal annealing. / Saher, Saim; Meffert, Matthias; Störmer, Heike; Gerthsen, Dagmar; Bouwmeester, Henny J.M.

In: Journal of materials chemistry. A, Vol. 5, No. 10, 2017, p. 4982-4990.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Grain-size dependence of the deterioration of oxygen transport for pure and 3 mol% Zr-doped Ba0.5Sr0.5Co0.8Fe0.2O3-δ induced by thermal annealing

AU - Saher, Saim

AU - Meffert, Matthias

AU - Störmer, Heike

AU - Gerthsen, Dagmar

AU - Bouwmeester, Henny J.M.

PY - 2017

Y1 - 2017

N2 - In this study, the influence of long-term annealing at intermediate temperatures on oxygen transport of Ba0.5Sr0.5Co0.8Fe0.2O3 d (BSCF) and 3 mol% Zr-doped BSCF (BSCF-Z3) ceramics with different grain sizes was studied by means of in situ electrical conductivity relaxation (ECR) measurements. Ceramics with different grain sizes in the range of 3–80 mm were obtained by varying the temperature and dwell time during sintering. For both compositions, the apparent values of the chemical diffusion coefficient Dchem and surface exchange coefficient kchem extracted from the data of ECR measurements are found to decrease with the time of annealing. The strongly correlated decreases in Dchem and kchem, being greater in magnitude at a lower grain size and temperature, are observed significantly more pronounced for BSCF than for BSCF-Z3. The results from microstructural analysis provide a clear rationale for the observations from ECR. High-resolution transmission electron microscopy (TEM) images recorded before and after annealing under pure oxygen at 700 C for 13 d show excessive formation of hexagonal and plate-like lamellar precipitates at the grain boundaries and in the interior of grains of BSCF ceramics during the annealing process, whilst secondary phase formation is restricted solely to the grain boundary regions in BSCF-Z3. The possible importance of grain boundaries in determining the oxygen surface exchange kinetics is emphasized.

AB - In this study, the influence of long-term annealing at intermediate temperatures on oxygen transport of Ba0.5Sr0.5Co0.8Fe0.2O3 d (BSCF) and 3 mol% Zr-doped BSCF (BSCF-Z3) ceramics with different grain sizes was studied by means of in situ electrical conductivity relaxation (ECR) measurements. Ceramics with different grain sizes in the range of 3–80 mm were obtained by varying the temperature and dwell time during sintering. For both compositions, the apparent values of the chemical diffusion coefficient Dchem and surface exchange coefficient kchem extracted from the data of ECR measurements are found to decrease with the time of annealing. The strongly correlated decreases in Dchem and kchem, being greater in magnitude at a lower grain size and temperature, are observed significantly more pronounced for BSCF than for BSCF-Z3. The results from microstructural analysis provide a clear rationale for the observations from ECR. High-resolution transmission electron microscopy (TEM) images recorded before and after annealing under pure oxygen at 700 C for 13 d show excessive formation of hexagonal and plate-like lamellar precipitates at the grain boundaries and in the interior of grains of BSCF ceramics during the annealing process, whilst secondary phase formation is restricted solely to the grain boundary regions in BSCF-Z3. The possible importance of grain boundaries in determining the oxygen surface exchange kinetics is emphasized.

U2 - 10.1039/c6ta10454a

DO - 10.1039/c6ta10454a

M3 - Article

VL - 5

SP - 4982

EP - 4990

JO - Journal of materials chemistry. A

JF - Journal of materials chemistry. A

SN - 2050-7488

IS - 10

ER -