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Self‐Diffusion of Er and Hf in Polycrystalline Er 2 O 3 ‐Stabilized HfO 2
Author(s) -
TESCH R. J.,
WIRKUS C.D.,
BERARD M.F.
Publication year - 1982
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1982.tb10343.x
Subject(s) - crystallite , diffusion , analytical chemistry (journal) , grain boundary , volume (thermodynamics) , materials science , chemistry , phase (matter) , mineralogy , crystallography , thermodynamics , microstructure , physics , organic chemistry , chromatography
Tracer self‐diffusion coefficients for Er and Hf were measured in polycrystalline Er 2 O 3 ‐stabilized HfO 2 (fluorite phase) at compositions between 10 and 40 mol% Er 2 O 3 and temperatures between 1700° and 2033°C. In some instances, grain‐boundary coefficients were also determined. The Hf volume coefficients were generally slightly smaller than Er coefficients, but neither showed a strong composition dependence, a finding most likely attributable to extensive clustering of charged defects which apparently rendered a large proportion of the “notional” defects essentially immobile. The activation energies for volume coefficients were very large, ranging from 630 to 760 kJ‐mol −1 , and generally decreased with increasing Er 2 O 3 content.