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Thermodynamic Analysis of the Cubic–Tetragonal Phase Equilibria in the System ZrO 2 –YO 1.5
Author(s) -
Katamura Junji,
Sakuma Taketo
Publication year - 1997
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.1151-2916.1997.tb03173.x
Subject(s) - spinodal decomposition , tetragonal crystal system , spinodal , phase (matter) , diffusionless transformation , thermodynamics , field (mathematics) , diffraction , condensed matter physics , crystallography , chemistry , materials science , physics , crystal structure , mathematics , microstructure , martensite , optics , organic chemistry , pure mathematics
The cubic‐tetragonal (c‐t) phase equilibria in the system ZrO 2 ‐YO 1.5 are thermodynamically analyzed from Landau's phenomenological theory. The calculated c‐t two‐phase field is depicted as a miscibility gap with a sharp maximum and the spinodal region as originally predicted by Hillert and Sakuma. However, the observed c‐t two‐phase field and the spinodal region are better described by the present model. In addition, this model can be used to discuss the nature of the c‐t diffusionless transformation from the order parameter in contrast with the original model. The predicted change in the tetragonality of t‐ZrO 2 with YO 1.5 content is slightly different from that in the c/a axial ratio estimated from X‐ray diffraction analysis. The displacement of cations and anions may not take place simultaneously during the c‐t transformation.