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A Model to Compute Phase Diagrams in Oxides with Empirical or First‐Principles Energy Methods and Application to the Solubility Limits in the CaO–MgO System
Author(s) -
Tepesch Patrick D.,
Kohan Adrian F.,
Garbulsky Gerardo D.,
Ceder Gerbrand,
Coley Crystal,
Stokes Harold T.,
Boyer Larry L.,
Mehl Michael J.,
Burton Benjamin P.,
Cho Kyeongjae,
Joannopoulos John
Publication year - 1996
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.1151-2916.1996.tb08934.x
Subject(s) - phase diagram , thermodynamics , quantum , solubility , parameterized complexity , statistical physics , ionic bonding , cluster expansion , materials science , phase (matter) , chemistry , physics , ion , quantum mechanics , mathematics , algorithm
The CaO–MgO system is used as a prototype system to evaluate the accuracy of several energy and entropy approximations for predicting solid‐state phase diagrams in ionic materials. Configurational disorder between the cations is parameterized with the cluster expansion technique. The vibrational contribution to the free energy is incorporated with a harmonic model that accounts for the dependence of the vibrational density of states on the cation configuration. The CaO–MgO phase diagram can be predicted very accurately with quantum mechanical energy methods, without the use of any adjustable parameters. Published empirical potential parameters for the CaO–MgO system reproduce the qualitative features of the phase diagram but significantly underestimate the solubility limits. Parameters that reasonably reproduce the quantum mechanical results are presented.