Enthalpy of formation of intermetallic phases from Al–Li system by solution and direct reaction calorimetric method

Abstract

Abstract The formation enthalpy of the AlLi, Al 2 Li 3 and Al 4 Li 9 intermetallic phases was measured with the use of the two calorimetric techniques. The first phase was examined by the solution and the direct reaction calorimetric method, and the other two phases only by the solution method. The phases were prepared from Al and Li in a glove-box filled with high purity argon with a very low concentration of impurities. The X-ray diffraction investigations were conducted to confirm the structure of the prepared phases. Setaram MHTC 96 Line evo calorimeter was used for the measurements at 956 K ± 4 K. The prepared samples of the Al–Li phases, similar to Li, were held in a glove-box to be protected against the reaction with the components of air. Directly before the measurements, the samples of the phases and of Li were transferred into the calorimeter in a tight delivery device. The value of the formation enthalpy measured for the AlLi phase in the case of the solution and direct synthesis technique was equal to −20.7 ± 0.5 and −20.4 ± 0.2 kJ/mol at., respectively. The same thermodynamic function by the solution method for the Al 2 Li 3 and Al 4 Li 9 phases was equal to −19.1 ± 0.4 and −15.1 ± 0.2 kJ/mol at.