Thermodynamics Of Binary Lipo3-Pb(Po3)(2) Mixtures - Phase Diagram And Thermodynamic Study Of The Liquid

Study of solid-liquid phase diagram of LiPO3-Pb(PO3)(2) binary system, in certain calcination conditions, shows the existence of several metastable phasis. When heated at a temperature of 723 K the binary mixtures lead uncompletely to a defined compound Pb2Li(PO3). On heating these ternary solid mixtures, three eutectic reactions have been observed:LiPO3+Pb(PO3)(2)-->Liquid at a temperature of 793 K (1)LiPO3+ Pb2Li(PO3)(5)-->Liquid at a temperature of 843 K (2)Pb2Li(PO3)(5)+Pb(PO3)(2)-->Liquid at a temperature of 891 K (3)The metastable liquid phase appears in the system at temperature of 793 K. DTA experiments performed on the binary LiPO3-Pb(PO3)(2) mixtures, show a superposition of two diagrams. The first one is metastable and the second represents the stable equilibrium phase diagram.Measurements of liquid enthalpy of binary LiPO3-Pb(PO3)(2) system at temperature of 979.65 K were reported. The corresponding values were very small and so the binary system can be considered as athermal. Assuming an ideal behaviour, the liquidus curves in the metastable diagram were calculated and the eutectic reaction (LiPO3-Pb(PO3)(2)-->Liquid) was confirmed at 793 K.