Phase Equilibria and Crystallization of Melts in the System Na2O-BaO-SiO2



Phase-equilibrium studies of the liquidus surface of the Na2O-BaO-SiO2 system are presented. The system contains 5 ternary compounds, Na2Ba4Si10O25, Na2Ba4Si2O6, Na2Ba2Si2O7, X (probably Na2Ba18Si28O75), and Y (probably Na2Ba45Si73O192), all of which melt incongruently. Twenty-three liquidus invariant points, including 13 peritectics, 4 eutectics, and 6 thermal maxima, were located. Metastable crystallization reactions are commonly encountered, and some of the metastable equilibria are described.