Reinvestigation of the DyCl3-LiCl binary system phase diagram

The phase equilibria in the DyCl3-LiCl binary system were established on the basis of differential scanning calorimetry (DSC) measurements. One compound, namely Li3DyCl6, is formed in this system. It melts congruently at 768 K with enthalpy of 51.6 kJ mol(-1). DSC curves for eutectic composition and for compositions close to eutectic (on the left and right side of eutectic) are identical. Small effect related to the liquidus is shadowed by a big effect related to eutectic, and only one thermal effect is visible. This is the reason that eutectic composition can not be determined directly. The only possibility to determine it precisely is a creation of Tammann diagram. Two eutectics, namely LiCl-Li3DyCl6 and Li3DyCl6-DyCl3, located at DyCl3 mol fractions x = 0.206 (T = 746 K) and x = 0.542 (T = 674 K) were found from Tammann's plots, which predict, through application of the lever rule, the variation of the enthalpy associated with eutectic melting as a function of composition.