Phase equilibria modeling in Bi2O3-SrO-MnOx system

The selected pseudobinary, isothermal and isoactivity sections of the Bi2O3-SrO-MnOx phase diagram are constructed from the calculated phase equilibria. The starting point for the thermodynamic analysis were the assessments of the respective pseudobinary systems Bi2O3-SrO, Bi2O3-MnOx and SrO-MnOx. The only quaternary solid phase - the perovskite solid solution - is described in terms of the point defect model [Bi1-x3+Srx2+] [Mn1-x+2 delta 3+Mnx-2 delta 4+] [O-1-delta/3(2-) Va(delta/3)](3). The quaternary liquid is approximated by a phenomenological model using the liquid species Mn, MnO, MnO1.5, SrO, and BiO1.5 with only binary Redlich-Kister coefficients. The ab initio electronic structure calculations of cohesive energies are employed to evaluate the enthalpies of formation of some stoichiometric phases. (C) 2005 Elsevier Ltd. All rights reserved.