Raman spectroscopic studies of mixed crystals of NaNO3-KNO3 quenched from different temperatures: Evidence for limited solid solutions in the system

Raman spectroscopy was used as a complementary tool to thermal and x-ray me thods in phase equilibrium studies of the NaNO3-KNO3 system. Based on the m icroscopic structures of the system, the Raman technique confirmed the phas e diagrams obtained by thermal studies. Structural phase transitions of the R (3) over bar m solid solutions to limited solid solutions were detected and the solid solubilities of the limited solid solutions were determined. The continuous series of solid solutions was found to consist of three slig htly different structures and hence NaNO3-KNO3 should be a system with limi ted solid solutions, which appeared to fit better than the continuous solid solution model to the reported experimental observations in Raman, differe ntial scanning calorimetric and x-ray diffraction studies. Copyright (C) 19 99 John Wiley & Sons, Ltd.