Thermodynamic properties of melts of Mn-Sc(Y, Ln) systems

Partial and integral mixing enthalpies of melts of binary systems Mn-Sc and Mn-Y at 1873 and 1830 K, respectively, are determined by calorimetry. It is found that the minima of the mixing enthalpies are -7.1 +/- 0.4 and -3.2 +/- 0.2 kJ/mol at x (Mn) = 0.60 and 0.61, respectively. The initial partial mixing enthalpies of Sc and Y are -33.2 +/- 2.1 and -16.6 +/- 0.8 kJ/mol, respectively. The thermodynamic properties of melts of binary Mn-Sc(Y) systems are calculated using the ideal associated solution (IAS) model. It is found that the activities of the components exhibit slight negative deviations from the ideal solutions, and the excess Gibbs energies reach -3.0 and -1.6 kJ/mol, respectively.