Critical systematic investigation of the Cd-Ce system. Phase stability and Gibbs energies of formation and equilibria via thermodynamic description

The CALPHAD (CAlculation of PHAse Diagrams) technique is used in the critical remodeling of the Cd-Ce system. On the basis of new experimental data in the literature, the excess Gibbs energies of the solution phase expression (liquid, bcc, fcc, and hcp_A3) are described using the Redlich-Kister equation. Four compounds (Cd${}_3$Ce, Cd${}_6$Ce, Cd${}_{11}$Ce, and Cd${}_{17}$Ce${}_2$) are treated as stochiometric compounds. Two intermetallic compounds (Cd${}_2$Ce and Cd${}_{58}$Ce${}_{13}$), which exhibit a little homogeneity range, are treated as a two-sublattice model. Two thermodynamic models are used for the CdCe and bcc. Model I is to model the compound CdCe and bcc-Ce separately. Model II is to use the formula (Cd, Ce)${}_{0.5}$(Cd, Ce)${}_{0.5}$(Va)${}_3$ to describe the compound CdCe with a CsCl-type structure (B2) and cope with the disorder-order transition from bcc-A2 to bcc-B2. The present work shows that four eutectic reactions, three peritectic reactions, two eutectoid reactions, one peritectoid transformation and three congruent reactions are observed, and the stoichiometric compound Cd${}_{17}$Ce${}_2$ is only stable from 804 to 882 °C in the Cd-Ce system.