Compressive creep performance of strontium-deficient and strontium-excess S
rFeO3-delta materials has been investigated in the temperature range 800 de
grees -1000 degreesC and in the stress range 2.5-25 MPa. The absolute densi
ties of the strontium-deficient and strontium-excess materials are 4.99 and
5.25 g/cm(3), respectively, which corresponds to porosities of similar to2
% and 5%, respectively. Both materials contain secondary phases because of
the cation nonstoichiometry. The creep rate is faster for the strontium-def
icient material than the strontium-excess material. The stress exponent is
approximately unity, and the activation energy is 260 +/- 30 kJ/mol for bot
h materials. The results can be explained by a cation diffusion mechanism.
The present findings are discussed in relation to previous sintering data a
nd the possible application of these materials as oxygen-permeable membrane
s.