Valence state and ionic conduction in Mn‐doped MgO partially stabilized zirconia

The mechanism of the enhancement in the ionic conductivity resulting from cubic phase stabilization in MgO partially stabilized zirconia (MgPSZ) by Mn doping was studied by examining the local Zr‐O structure. Cubic phase (14 vol%) in MgPSZ was increased with the addition of MnO2, and 10 mol% Mn‐dope...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 2018-04, Vol.101 (4), p.1790-1795
Main Authors: Kim, Buyoung, Lee, Heesoo
Format: Article
Language:English
Subjects:
Conductivity
Doping
Ion currents
Ions
Magnesium oxide
Manganese dioxide
manganese/manganese compounds
Partially stabilized zirconia
phase transformations
Substitutes
Vacancies
X ray photoelectron spectroscopy
X‐ray methods
zirconia: partially stabilized
Zirconium
Zirconium dioxide
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Summary:The mechanism of the enhancement in the ionic conductivity resulting from cubic phase stabilization in MgO partially stabilized zirconia (MgPSZ) by Mn doping was studied by examining the local Zr‐O structure. Cubic phase (14 vol%) in MgPSZ was increased with the addition of MnO2, and 10 mol% Mn‐doped MgPSZ exhibited the highest cubic phase fraction (98.72%), which was analyzed by Rietveld refinement. In addition, only the cubic phase, not the monoclinic and tetragonal phases, was observed in the TEM‐SAED pattern of 10 mol% Mn‐doped MgPSZ. Doped Mn exhibited a high Mn2+/Mn4+ ratio, which was identified by X‐ray photoelectron spectroscopy (XPS). In addition, it indicates that oxygen vacancy formation by substitution of Mn2+ in the Zr4+ site in MgPSZ increased cubic phase fraction. Ionic conductivity of MgPSZ was improved by the cubic phase increase attributed to Mn doping, and 10 mol% Mn‐doped MgPSZ exhibited higher ionic conductivity than MgPSZ. To investigate the mechanism of the ionic conductivity improvement, Zr‐O local structure in Mn‐doped MgPSZ was analyzed by Zr K‐edge EXAFS of MgPSZ, and the number of bonding of the Zr‐O first shell decreased with increased Mn substitution. Therefore, it was considered that the oxygen vacancy generation led to an increase in the cubic phase and the number of ionic conduction sites.
ISSN:0002-7820
1551-2916
DOI:10.1111/jace.15333