Premium
Thermodynamic Modeling of the Miscibility Gaps and the Metastable Liquidi in the MgO‐SiO 2 , CaO‐SiO 2 , and SrO‐SiO 2 Systems
Author(s) -
Kim Sung S.,
Sanders Thomas H.
Publication year - 1999
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.1151-2916.1999.tb02014.x
Subject(s) - liquidus , spinodal decomposition , metastability , thermodynamics , phase diagram , materials science , spinodal , crystallization , solid solution , extrapolation , microstructure , ceramic , phase (matter) , mineralogy , chemistry , metallurgy , physics , mathematics , organic chemistry , alloy , mathematical analysis
A range of compositions and temperatures below the monotectic temperature exists where there are thermodynamic restrictions that prevent the equilibrium solid from forming directly from the undercooled homogeneous liquid. In this region, the solid can form only after liquid‐liquid phase separation has occurred. As suggested by earlier research, the thermodynamic restrictions on the crystallization process may be useful to control the crystallized grain structure in glass‐ceramic systems. Thus, understanding the thermodynamic limitations on the formation of the solid in monotectic systems could have commercial significance. In the present paper, the metastable liquidus boundaries, liquid miscibility gaps, and spinodal curves in binary MgO‐SiO 2 , CaO‐SiO 2 , and SrO‐SiO 2 systems are calculated by using analytical expressions for the Gibbs free energies of the liquid phases. Calculating the metastable liquidus rather than using a simple extrapolation as originally proposed in the aforementioned previous research provides greater control of the heat‐treatment processes and, thus, greater control over the resulting microstructure.