CHARACTERISTICS OF TRANSITION-METAL OXIDE DOPING OF YSZ - STRUCTURE AND ELECTRICAL-PROPERTIES

Citation
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
ISSN journal
09565000
Volume
92
Issue
12
Year of publication
1996
Pages
2173 - 2178
Database
ISI
SICI code
0956-5000(1996)92:12<2173:COTODO>2.0.ZU;2-D
Abstract
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.