Enthalpy of formation of the CaLi2 phase

The solution calorimetric method was used for the determination of the formation enthalpy of the CaLi2 intermetallic phase and the heat of solution of the components. The phase was prepared in a glove box with high purity argon protective atmosphere by means of melting proper amounts of calcium and lithium in a molybdenum crucible at 350 °C (623 K). The X-ray structure analysis confirms the existence only the CaLi2 phase in the alloy. With the application of liquid aluminum and tin as the metallic bath, the calorimetric investigations were conducted at 746 °C (1019 K) and 399 °C (672 K), as well as 853 °C (1126 K). On the basis of the data from this study and from the literature, the temperature dependencies of the heat of solution of the calcium and lithium in the liquid aluminum and tin were determined in the form of linear equations. The formation enthalpies of the CaLi2 intermetallic phase obtained in these two types of investigations are comparable to each other and they are equal to −2.7 ± 1.3 and −2.9 ± 1.7 kJ/g-atoms for the Al and Sn-bath, respectively.