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Subsolidus Equilibria in the TiO 2 ‐SnO 2 System
Author(s) -
PARK M.,
MITCHELL T. E.,
HEUER A. H.
Publication year - 1975
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.1151-2916.1975.tb18980.x
Subject(s) - spinodal decomposition , spinodal , thermodynamics , phase boundary , work (physics) , solid solution , chemistry , miscibility , materials science , phase (matter) , condensed matter physics , mineralogy , physics , polymer , organic chemistry
The subsolidus miscibility gap for the TiO 2 ‐SnO 2 system was redetermined. The critical temperature, 1430°C, is intermediate between that determined by Padurow, 1330°C, and that determined by Garcia and Speidel, 1475°C. Although the phase boundary is slightly asymmetric (the critical composition occurs at 47 mol% TiO 2 ), it fits the regular‐solution model down to 1200°C. Calculations of the coherent spinodal using the regular‐solution model indicated depression of the spinodal below T c , by 105°, 310°, and 387° for composition fluctuations along the [001], <101>, and <100> directions, respectively. These depressions of the spinodal are much greater than those calculated by Stubican and Schultz; this discrepancy is believed to result from an error in the latter workers’ calculations. During the present work, positive deviations from Vegard's law were found in this system. Both the magnitude and the sign of the deviation can be predicted using a theory based on nonlinear second‐order elasticity.