Continuum mechanics simulations of NiO/Ni-YSZ composites during reduction and re-oxidation

Mikko, H. Pihlatie (Corresponding Author), H.L. Frandsen, A. Kaiser, M. Mogensen

Research output: Contribution to journalArticleScientificpeer-review

49 Citations (Scopus)

Abstract

Repeated reduction–oxidation (redox) cycles on Ni-based solid oxide fuel cells (SOFC) have been experimentally well investigated and are known to be detrimental to the thermomechanical stability of the composites, especially on anode supported structures. In the present work the mechanistic analysis of the internal factors leading to the dimensional changes and the thermomechanical instability have been addressed, to our knowledge for the first time, using continuum mechanics simulations. The two intertwined percolating phases, YSZ and NiO/Ni, interact and the driving force for the dimensional change arises from the volumetric change related to the phase change NiO ↔ Ni. The measurable change in bulk length is given by the ceramic YSZ backbone as a response to the stress created by the chemical strain. The different subprocesses described in the model for YSZ were elastic and anelastic expansion, diffusional creep, grain boundary sliding (GBS) and microcracking due to excessive stress. In the Ni/NiO phase, nonelastic strains in terms of diffusional and power law creep were implemented, and additionally for NiO deformation due to microcracking and/or pseudoplasticity. Semi-empirical correlations were employed for creep limiting grain growth of Ni and NiO, particle coarsening of Ni and particle growth in NiO during the oxidation. Seven experimental cases of high temperature redox dilatometry were simulated. The model shows good qualitative agreement with the measurements. The different processes of importance for the dimensional behaviour are discussed.
Original languageEnglish
Pages (from-to)2677-2690
JournalJournal of Power Sources
Volume195
Issue number9
DOIs
Publication statusPublished - 2010
MoE publication typeA1 Journal article-refereed

Fingerprint

continuum mechanics
Continuum mechanics
yttria-stabilized zirconia
Microcracking
Creep
Oxidation
oxidation
composite materials
Composite materials
dilatometry
Grain boundary sliding
simulation
Coarsening
solid oxide fuel cells
Solid oxide fuel cells (SOFC)
Grain growth
sliding
Anodes
anodes
grain boundaries

Keywords

  • SOFC
  • Ni-YSZ
  • Redox stability
  • Continuum mechanics
  • Creep
  • Viscoelastic

Cite this

Pihlatie, Mikko, H. ; Frandsen, H.L. ; Kaiser, A. ; Mogensen, M. / Continuum mechanics simulations of NiO/Ni-YSZ composites during reduction and re-oxidation. In: Journal of Power Sources. 2010 ; Vol. 195, No. 9. pp. 2677-2690.
@article{2d0fb4562a224eceb8d3faa58dcc3180,
title = "Continuum mechanics simulations of NiO/Ni-YSZ composites during reduction and re-oxidation",
abstract = "Repeated reduction–oxidation (redox) cycles on Ni-based solid oxide fuel cells (SOFC) have been experimentally well investigated and are known to be detrimental to the thermomechanical stability of the composites, especially on anode supported structures. In the present work the mechanistic analysis of the internal factors leading to the dimensional changes and the thermomechanical instability have been addressed, to our knowledge for the first time, using continuum mechanics simulations. The two intertwined percolating phases, YSZ and NiO/Ni, interact and the driving force for the dimensional change arises from the volumetric change related to the phase change NiO ↔ Ni. The measurable change in bulk length is given by the ceramic YSZ backbone as a response to the stress created by the chemical strain. The different subprocesses described in the model for YSZ were elastic and anelastic expansion, diffusional creep, grain boundary sliding (GBS) and microcracking due to excessive stress. In the Ni/NiO phase, nonelastic strains in terms of diffusional and power law creep were implemented, and additionally for NiO deformation due to microcracking and/or pseudoplasticity. Semi-empirical correlations were employed for creep limiting grain growth of Ni and NiO, particle coarsening of Ni and particle growth in NiO during the oxidation. Seven experimental cases of high temperature redox dilatometry were simulated. The model shows good qualitative agreement with the measurements. The different processes of importance for the dimensional behaviour are discussed.",
keywords = "SOFC, Ni-YSZ, Redox stability, Continuum mechanics, Creep, Viscoelastic",
author = "Pihlatie, {Mikko, H.} and H.L. Frandsen and A. Kaiser and M. Mogensen",
year = "2010",
doi = "10.1016/j.jpowsour.2009.11.079",
language = "English",
volume = "195",
pages = "2677--2690",
journal = "Journal of Power Sources",
issn = "0378-7753",
publisher = "Elsevier",
number = "9",

}

Continuum mechanics simulations of NiO/Ni-YSZ composites during reduction and re-oxidation. / Pihlatie, Mikko, H. (Corresponding Author); Frandsen, H.L.; Kaiser, A.; Mogensen, M.

In: Journal of Power Sources, Vol. 195, No. 9, 2010, p. 2677-2690.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Continuum mechanics simulations of NiO/Ni-YSZ composites during reduction and re-oxidation

AU - Pihlatie, Mikko, H.

AU - Frandsen, H.L.

AU - Kaiser, A.

AU - Mogensen, M.

PY - 2010

Y1 - 2010

N2 - Repeated reduction–oxidation (redox) cycles on Ni-based solid oxide fuel cells (SOFC) have been experimentally well investigated and are known to be detrimental to the thermomechanical stability of the composites, especially on anode supported structures. In the present work the mechanistic analysis of the internal factors leading to the dimensional changes and the thermomechanical instability have been addressed, to our knowledge for the first time, using continuum mechanics simulations. The two intertwined percolating phases, YSZ and NiO/Ni, interact and the driving force for the dimensional change arises from the volumetric change related to the phase change NiO ↔ Ni. The measurable change in bulk length is given by the ceramic YSZ backbone as a response to the stress created by the chemical strain. The different subprocesses described in the model for YSZ were elastic and anelastic expansion, diffusional creep, grain boundary sliding (GBS) and microcracking due to excessive stress. In the Ni/NiO phase, nonelastic strains in terms of diffusional and power law creep were implemented, and additionally for NiO deformation due to microcracking and/or pseudoplasticity. Semi-empirical correlations were employed for creep limiting grain growth of Ni and NiO, particle coarsening of Ni and particle growth in NiO during the oxidation. Seven experimental cases of high temperature redox dilatometry were simulated. The model shows good qualitative agreement with the measurements. The different processes of importance for the dimensional behaviour are discussed.

AB - Repeated reduction–oxidation (redox) cycles on Ni-based solid oxide fuel cells (SOFC) have been experimentally well investigated and are known to be detrimental to the thermomechanical stability of the composites, especially on anode supported structures. In the present work the mechanistic analysis of the internal factors leading to the dimensional changes and the thermomechanical instability have been addressed, to our knowledge for the first time, using continuum mechanics simulations. The two intertwined percolating phases, YSZ and NiO/Ni, interact and the driving force for the dimensional change arises from the volumetric change related to the phase change NiO ↔ Ni. The measurable change in bulk length is given by the ceramic YSZ backbone as a response to the stress created by the chemical strain. The different subprocesses described in the model for YSZ were elastic and anelastic expansion, diffusional creep, grain boundary sliding (GBS) and microcracking due to excessive stress. In the Ni/NiO phase, nonelastic strains in terms of diffusional and power law creep were implemented, and additionally for NiO deformation due to microcracking and/or pseudoplasticity. Semi-empirical correlations were employed for creep limiting grain growth of Ni and NiO, particle coarsening of Ni and particle growth in NiO during the oxidation. Seven experimental cases of high temperature redox dilatometry were simulated. The model shows good qualitative agreement with the measurements. The different processes of importance for the dimensional behaviour are discussed.

KW - SOFC

KW - Ni-YSZ

KW - Redox stability

KW - Continuum mechanics

KW - Creep

KW - Viscoelastic

U2 - 10.1016/j.jpowsour.2009.11.079

DO - 10.1016/j.jpowsour.2009.11.079

M3 - Article

VL - 195

SP - 2677

EP - 2690

JO - Journal of Power Sources

JF - Journal of Power Sources

SN - 0378-7753

IS - 9

ER -