| Abstract Scope |
The Co-Ge-Sb system has attracted intensive research interest since it has various compounds with promising thermoelectric properties. Phase equilibrium information is fundamentally important. This study determined the Co-Ge-Sb phase equilibria by both experimental measurements and the Calphad-type modeling. Equilibrated alloys were prepared with pure elements. At 600 °C, a ternary compound, Co3Ge2Sb, is found and there are totally fourteen single-phase regions: α-Co, ε-Co, Ge, Sb, Liquid, CoSb, CoSb2, CoSb3, β-Co5Ge3, CoGe2, CoGe, Co5Ge2, Co5Ge7 and Co3Ge2Sb in the Co-Ge-Sb system. Calphad-type modeling is conducted based on the phase diagrams of its three constituent binary systems and the experimental results determined in this study. The phases Co5Ge2, Co5Ge7, CoGe, CoGe2, CoSb, CoSb2, CoSb3, and Co3Ge2Sb were described using stoichiometric models, while β-Co5Ge3 was described using a sublattice model, and the two liquid phases were described using solution models. The calculated phase diagrams are in good agreement with the experimental results. |