Pyrochlore to Fluorite Transition: The Y2(Ti1-xZrx)2O7 (0.0 ≤ x ≤ 1.0) System
Artikel i vetenskaplig tidskrift, 2012

The structural properties of the system Y-2(Ti1-xZrx)(2)O-7 have been investigated using the neutron powder diffraction technique, including a detailed analysis of the "total scattering" using reverse Monte Carlo modeling to probe the short-range ion-ion correlations over sample range 0.0 <= x <= 1.0. The average crystal structure shows a continuous transformation from the long-range ordered pyrochlore structure (Fd (3) over barm, a = 10.0967(1) angstrom, Z = 8, for x = 0.00, Y2Ti2O7) to a disordered fluorite structure (Fm (3) over barm, a = 5.2042(1) angstrom, Z = 1, for x = 1.00, Zr2Y2O7) in agreement with previous reports. However, on increasing x the disordering of both the cation and the anion sublattices occurs in stages, with the Zr4+ initially only substituting onto the Ti4+ site and adopting a cubic, rather than octahedral, local anion environment. At concentrations in excess of x approximate to 0.4 there is a gradual disordering of the Y3+, Ti4+, and Zr4+ species over all the cation sites, coupled with a redistribution of the O2- which initially only involves those anions on the O1 sites. The relationship between the composition dependences of the structure properties and the ionic conductivity is discussed.

zro2-tio2-y2o3 system

chemistry

oxygen vacancy ordering

electrical-conductivity

titania

oxygen-ion

y2ti2o7

oxide fuel-cells

zirconia

phase

anode materials

RMC modeling

SOFC electrolytes

Författare

Stefan Norberg

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

S. Hull

ISIS Facility

Sten Eriksson

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

Istaq Ahmed

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

FRANCIS GACHAO KINYANJUI

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

J. J. Biendicho

ISIS Facility

Stockholms universitet

Chemistry of Materials

0897-4756 (ISSN) 1520-5002 (eISSN)

Vol. 24 22 4294-4300

Ämneskategorier

Kemi

DOI

10.1021/cm301649d