Critical evaluation and thermodynamic CALPHAD reassessment of Cerium–Nickel system

ABSTRACT

This paper focuses on the development of thermodynamic databases for rare-earth–Nickel (RE–Ni) through the optimisation of the Ce–Ni binary system using the CALPHAD (CALculation of PHAse Diagrams) approach. The authors critically reviewed the literature on thermodynamic and phase diagram information and took into account the integral enthalpies of mixing of the liquid phase and the solubility of Ni in pure Ce, which were ignored in most previous studies. Two-sublattice models were employed to accurately describe the homogeneity ranges of CeNi₅ phases. The paper presents an optimal set of thermodynamic parameters that express the Gibbs energy of liquid and solid phases. The resulting phase diagram, coordinates of invariant equilibria, and thermodynamic properties are compared with those from previous assessments, demonstrating significant progress. The tendency of the formation enthalpies of the RE–Ni binary systems as a function of the RE atomic number has been discussed systematically.

KEYWORDS:

• Ce–Ni system
• Intermetallic phases
• Computational thermodynamics
• Calphad approach
• Gibbs free energy

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