Phase Diagram Cuspidine (3CaO . 2SiO2 . CaF2)-CaF2

Equilibrium phase diagram for the system cuspidine (3CaO · 2SiO2 · CaF2)-CaF2 has been studied by the quenching method and differential thermal analysis (DTA). Hermetically closed platinum capsules were used in both methods to prevent fluorine loss in the form of HF and SiF4 by reaction of the CaF2 with water vapor or SiO2. Cuspidine congruently melts at 1680 ± 2 K. The cuspidine-CaF2 system presents a simple eutectic type of phase diagram. The eutectic composition and temperature are 46 mass pct 3CaO · 2SiO2 - 54 mass pct CaF2 and 1515 ± 3 K, respectively.