The binary systems SrSiO3-SiO2 and SrSiO3-BaSiO3 have been studied exp
erimentally by DTA analysis. No compounds exist in the SrSiO3-SiO2 SyS
tem. In the SrSiO3-BaSiO3 system major solid solubility areas exist, a
nd a ternary phase has been identified at ca. 80 mol% BaSiO3. From the
two binary systems thus obtained, and the binary system BaSiO3-SiO2 t
aken from literature, the excess thermodynamic functions have been det
ermined to calculate the ternary system BaSiO3-SrSiO3-SiO2.