Compressive high-temperature deformation of BaCe1-xYxO3-y polycrystals as a
function of yttrium content (x = 0.05, 0.1, 0.15, and 0.2) was conducted i
n controlled oxygen partial pressures of 0.1-2 X 10(4) Pa at 1200-1400 degr
ees C to determine deformation kinetics and the rate-controlling species fo
r diffusional creep. Creep rate was independent of oxygen partial pressure
and the steady-state creep rate increased with increasing Y content. The re
sults can be explained on the basis of a grain-boundary-sliding creep mecha
nism in which the rate-controlling species are Ba or Ce interstitials. A si
mple point-defect model was used to describe the results. (C) 1999 Elsevier
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