The thermodynamic assessment of the Co-Sb system

The Co-Sb system has been assessed thermodynamically based on the experimental data of both the phase equilibria and the thermochemical properties. The reasonable models were constructed for all the phases of the system. The liquid and the terminal solid solution phases, (αCo) and (εCo), were described as the substitutional solution model while the (Sb) phase was treated as the pure element Sb for lack of the solubility data of Co in (Sb). The (βCoSb) phase was modelled by three-sublattices, Sb: Co, Va: Va, Co, since its structure is of the NiAs-type (B81) with the Co vacancies on the Sb-rich side and the interstitial Co atoms on the Co-rich side. The compounds γCoSb2 and δCoSb3 were expressed as the stoichiometric compounds. Much attention has been paid to the consistence between the experimental measurements and the theoretical calculations. Using the present thermodynamic data, the calculation results can reproduce the experimental data well.