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JMR Abstracts: September 1998
Article
High-temperature creep resistance in rare
earth-doped fine-grained
Al2O3
H. Yoshida, Y. Ikuhara, T. Sakuma
(The University of Tokyo)
<*p(0,21.6,0,9.5,0,0,g,"U.S.
English")$f"Helvetica-Condensed">High-temperature creep in undoped
Al2O3 and
La2O3- or
Y2O3- or
Lu2O3-doped
Al2O3 with a grain size of
about 1 <>mm is examined in uniaxial
compression testing at temperatures between 1150 and 1350°C. The
high-temperature creep resistance in
Al2O3 is highly improved
by the rare-earth oxide doping in the level of 0.045 mol%, and the creep
rate is suppressed in the order
La2O3
Y2O3
Lu2O3. Rare-earth ions in
each doped Al2O3 are found
to segregate in Al2O3
grain boundaries without forming amorphous phase or second-phase
particles. The activation energy for creep in undoped
Al2O3 is estimated to be
410 kJ/mol, while it is about 800 kJ/mol in the three rare-earth
oxide-doped Al2O3. The
grain boundary diffusivity must be highly reduced by the segregation of
the dopant cation in Al2O3
grain boundaries.
Order No.:
JA809-035 © 1998 MRS
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