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Cation Interdiffusion and Phase Stability in Polycrystalline Tetragonal Ceria–Zirconia–Hafnia Solid Solution
Author(s) -
Sakka Yoshio,
Oishi Yasumichi,
Ando Ken,
Morita Shoji
Publication year - 1991
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.1151-2916.1991.tb06808.x
Subject(s) - solid solution , tetragonal crystal system , crystallite , ionic radius , materials science , grain boundary , fluorite , analytical chemistry (journal) , phase boundary , thermal diffusivity , phase (matter) , mineralogy , crystallography , ion , thermodynamics , chemistry , crystal structure , microstructure , metallurgy , physics , organic chemistry , chromatography
Zr–Hf interdiffusions were carried out at 1350° to 1520°C for polycrystalline tetragonal solid solutions of 14CeO 2 ·86(Zr 1‐ x Hf x )O 2 with X = 0.02 and 0.10. Lattice and grain‐boundary interdiffusion parameters were calculated from the concentration distributions by using Oishi and Ichimura's equation. Lattice interdiffusion coefficients were described by D = 3.0 × 10 3 exp[‐623 (kJ/mol)/ RT ] cm 2 /s and grain‐boundary interdiffusion parameters by δ D ' = 0.29 exp[‐506 (kJ/mol)/ RT ] cm 3 /s. The cation diffusivity was lower than the anion diffusivity. The results were compared with diffusivities in the fluorite‐cubic solid solution. The critical grain radii for stabilization of the tetragonal phase in CeO 2 ‐doped ZrO 2 were 11 and 6 μm for the solutions with 2 and 10 mol% HfO 2 substitution, respectively, both of which are much greater than in the Y 2 O 3 ‐doped ZrO 2 solid solution.