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@ARTICLE{Niedrig:16240,
      author       = {Niedrig, C. and Taufall, S. and Burriel, M. and Menesklou,
                      W. and Wagner, S.F. and Baumann, S. and Ivers-Tiffée, E.},
      title        = {{T}hermal {S}tability of the {C}ubic {P}hase in
                      {B}a0.5{S}r0.5{C}o0.8{F}e0.2{O}3- ({BSCF})},
      journal      = {Solid state ionics},
      volume       = {197},
      issn         = {0167-2738},
      address      = {Amsterdam [u.a.]},
      publisher    = {Elsevier Science},
      reportid     = {PreJuSER-16240},
      pages        = {25 - 31},
      year         = {2011},
      note         = {Financial support from the Helmholtz Association of German
                      Research Centres (Initiative and Networking Fund) through
                      the MEM-BRAIN Helmholtz Alliance (www.mem-brain-allianz.eu)
                      is gratefully acknowledged. The authors also thank the
                      German Federal Ministry of Economics and Technology (BMWi
                      grant no. 0327803F) and the DFG-Research Center for
                      Functional Nanostructures (CFN, project F2.1) for funding.},
      abstract     = {Ba0.5Sr0.5Co0.8Fe0.2O0-delta (BSCF) is a material with
                      excellent oxygen ionic and electronic transport properties
                      reported by many research groups. In its cubic phase, this
                      mixed ionic-electronic conducting (MIEC) perovskite is a
                      promising candidate for oxygen permeation membranes. For
                      this application, its long-term stability under operating
                      conditions (especially temperature and oxygen partial
                      pressure) is of crucial importance.The present work is
                      focused on the thermal stability of the BSCF cubic phase in
                      the targeted temperature range for applications (700 ... 900
                      degrees C) in light of previous studies in literature
                      reporting a reversible transition to a hexagonal phase
                      somewhere below 900 degrees C.To this end, single phase
                      cubic BSCF powders were annealed at different temperatures
                      over varying periods of time. Phase composition was
                      subsequently analysed by X-ray diffractometry (XRD) in order
                      to determine both the temperature limit and the time-scale
                      for the formation of the hexagonal phase. Additionally, the
                      long-term behaviour of the electrical conductivity was
                      examined on bulk samples at 700 degrees C, 800 degrees C and
                      900 degrees C over several hundreds of hours, showing a
                      prolonged decrease at 800 degrees C. The decrease in
                      electrical conductivity at this temperature was also
                      examined on bulk samples with different grain sizes, showing
                      a more pronounced decrease the smaller the average grain
                      size. Coexistence of both phases (cubic and hexagonal) could
                      also be shown for 700 degrees C, however with a different
                      phase equilibrium than at 800 degrees C. (C) 2011 Elsevier
                      B.V. All rights reserved.},
      keywords     = {J (WoSType)},
      cin          = {IEK-1},
      ddc          = {530},
      cid          = {I:(DE-Juel1)IEK-1-20101013},
      pnm          = {Rationelle Energieumwandlung},
      pid          = {G:(DE-Juel1)FUEK402},
      shelfmark    = {Chemistry, Physical / Physics, Condensed Matter},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000295572000004},
      doi          = {10.1016/j.ssi.2011.06.010},
      url          = {https://juser.fz-juelich.de/record/16240},
}