Thermodynamic assessment of the Co–Th and Fe–Th systems

The thermodynamic assessments of the Co–Th and Fe–Th binary systems were carried out by using the calculation of phase diagrams (CALPHAD) method on the basis of the experimental data including the thermodynamic properties and phase equilibria. The Gibbs free energies of the liquid, bcc, fcc, and hcp phases were described by subregular solution model with the Redlich–Kister equation, and those of the intermetallic compounds (Co17Th2, Co5Th, Co7Th2, CoTh, Co3Th7, Fe17Th2, Fe5Th, Fe7Th2, Fe3Th and Fe3Th7) in these two binary systems were described by sublattice model. The thermodynamic parameters of the Co–Th and Fe–Th binary systems were optimized for reproducing the experimental data, respectively, and an agreement between the calculated results and experimental data was obtained in each binary system.