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@PHDTHESIS{HasdinorBinHassan:10871,
      author       = {Hasdinor Bin Hassan, Oskar},
      title        = {{O}xides with polyatomic anions considered as new
                      electrolyte materials for solid oxide fuel cells ({SOFC}s)},
      volume       = {68},
      issn         = {1866-1793},
      school       = {Ruhr-Universität Bochum},
      type         = {Dr. (Univ.)},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {PreJuSER-10871},
      isbn         = {978-3-89336-633-0},
      series       = {Schriften des Forschungszentrums Jülich : Energie $\&$
                      Umwelt / Energy $\&$ Environment},
      pages        = {VII, 121 S.},
      year         = {2010},
      note         = {Record converted from VDB: 12.11.2012; Ruhr-Univ. Bochum,
                      Diss., 2010},
      abstract     = {Materials with Polyatomic anions of [Al$_{2}$O$_{7}]^{-8}$,
                      [Ti$_{2}$O$_{8}]^{-8}$ and [P$_{2}$O$_{7}]^{-4}$ were
                      investigated with respect to their ionic conductivity
                      properties as well as its thermal expansion properties with
                      the aim to use them as SOFCs electrolytes. The polyatomic
                      anion groups selected from the oxy-cuspidine family of
                      Gd$_{4}$Al$_{2}$O$_{9}$ and Gd$_{4}$Ti$_{2}$O$_{10}$ as well
                      as from pyrophosphate SnP$_{2}$O$_{7}$. The pure
                      oxy-cuspidine Gd$_{4}$Al$_{2}$O$_{9}$, the series of
                      Gd$_{4}$Al$_{2-x}$Mg$_{x}$O$_{9-x/2}$ with x = 0.10–1.0
                      and Gd$_{4-x}$M$_{x}$Al$_{2}$O$_{9-x/2}$ (M=Ca, Sr) with x =
                      0.05–0.5 were prepared successfully by the citrate
                      complexation method. All samples showed the crystal
                      structure of monoclinic oxycuspidine structure with space
                      group of P2$_{1}$/c and Z=4. No solid solution was observed
                      for Gd$_{4}$Al$_{2-x}$Mg$_{x}$O$_{9-x/2}$ where additional
                      phases of Gd$_{2}$O$_{3}$ and MgO were presence. XRD
                      semiquantitative analysis together with SEM-EDX analysis
                      revealed that Mg$^{2+}$ was not able to substitute the
                      Al$^{3+}$ ions even at low Mg$^{2+}$ concentration. The
                      solid solution limit of
                      Gd$_{4-x}$Ca$_{x}$Al$_{2}$O$_{9-x/2}$ and
                      Gd$_{4-x}$Sr$_{x}$Al$_{2}$O$_{9-x/2}$ was determined between
                      0.05-0.10 and 0.01-0.05 mol for Ca and Sr, respectively.
                      Beyond the substitution limit Gd$_{4}$Al$_{2}$O$_{9}$,
                      GdAlO$_{3}$ and SrGd$_{2}$Al$_{2}$O$_{7}$ appeared as
                      additional phases. The highest electrical conductivity
                      obtained at 900 °C yielded $\sigma$ = 1.49 x 10$^{-4}$
                      Scm$^{-1}$ for Gd$_{3.95}$Ca$_{0.05}$Al$_{2}$O$_{8.98}$. In
                      comparison, the conductivity of pure Gd$_{4}$Al$_{2}$O$_{9}$
                      was $\sigma$ = 1.73 x 10$^{-5}$ Scm$^{-1}$. The
                      conductivities determined were in a similar range as those
                      of other cuspidine materials investigated previously. The
                      thermal expansion coefficient of Gd$_{4}$Al$_{2}$O$_{9}$ at
                      1000 °C was 7.4 x 10$^{-6}$ K$^{-1}$. The earlier reported
                      phase transition between 1100 and 1200 °C changed with
                      increasing substitution of Ca and Sr. Consequently, the
                      analogue materials of pure oxy-cuspidine
                      Gd$_{4}$Ti$_{2}$O$_{10}$, the series of
                      Gd$_{4}$Ti$_{2-x}$Mg$_{x}$O$_{10-x/2}$ with x=0.05 - 0.50
                      and the series Gd$_{4-x}$M$_{x}$Ti$_{2}$O$_{10-x/2}$ (M=Ca,
                      Sr) with x=0.05 - 0.50 were prepared successfully also by
                      the citrate complexation method. All samples show the
                      crystal structure of orthorhombic oxy-cuspidine structure
                      with space group of Pnma and Z=4. No solid solution was
                      observed for Gd$_{4}$Ti$_{2-x}$Mg$_{x}$O$_{10-x/2}$ where
                      additionally phase of monoclinic Gd$_{2}$O$_{3}$ was
                      present. The solid solution limit of
                      Gd$_{4-x}$Ca$_{x}$Ti$_{2}$O$_{10-x/2}$ and
                      Gd$_{4-x}$Sr$_{x}$Ti$_{2}$O$_{10-x/2}$ was determined
                      between 0.20-0.30 and 0.05-0.10 mol for Ca and Sr,
                      respectively. Beyond the substitution limit, GdTiO$_{3}$ and
                      SrTiO$_{3}$ appeared as additional phases, respectively. The
                      highest electrical conductivity obtained at 900 °C yielded
                      $\sigma$ = 2.50 x 10$^{-4}$ Scm$^{-1}$ for
                      Gd$_{3.80}$Ca$_{0.20}$Ti$_{2}$O$_{9.90}$. In comparison, the
                      conductivity of pure Gd$_{4}$Ti$_{2}$O$_{10}$ was $\sigma$ =
                      3.10 x 10$^{-5}$ Scm$^{-1}$. Again the conductivities
                      determined were in a similar range as those of other
                      cuspidine materials investigated previously. The thermal
                      [...]},
      cin          = {IEF-1},
      ddc          = {333.7},
      cid          = {I:(DE-Juel1)VDB809},
      pnm          = {Rationelle Energieumwandlung},
      pid          = {G:(DE-Juel1)FUEK402},
      typ          = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
      url          = {https://juser.fz-juelich.de/record/10871},
}