Xj. Huang et W. Weppner, CHARACTERISTICS OF TRANSITION-METAL OXIDE DOPING OF YSZ - STRUCTURE AND ELECTRICAL-PROPERTIES, Journal of the Chemical Society. Faraday transactions, 92(12), 1996, pp. 2173-2178
Citations number
23
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
TiO2, Mn2O3, Tb4O7, Nb2O5 and WO3 can be doped into yttria-stabilised
zirconia (YSZ) and from solid-state solutions. Five basic characterist
ics are found: (1) The phase of zirconia can be controlled by changing
the oxygen vacancy concentration by doping. Dopants with valences low
er than four tend to increase the oxygen vacancy concentration [V-0 ''
] and may convert ZrO2 . 3Y(2)O(3) from the tetragonal to the cubic ph
ase; dopants with valences higher than four tend to reduce [V-0 ''] an
d may convert ZrO2 . 8Y(2)O(3) from the cubic phase to the tetragonal
phase. (2) p- or n-type conducting behaviour of the semiconducting dop
ant is maintained regardless of the change in the chemical environment
. It is shown that the oxygen partial pressure dependence of the conce
ntrations of holes and electrons is mainly determined by the dopants,
i.e., the type and amount of transition metal oxide and yttria, which
is an amphoteric semiconductor. (3) The ionic conductivity decreases w
hen large amounts of dopants cause local lattice distortion. (4) The d
iffusion coefficients of electrons and ions are correlated. (5) The el
ectrochemical redox potential of the dopant shows no obvious change wh
en it is doped onto zirconia.