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, (alpha Co) and (epsilon Co), 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 (beta CoSb) phase was modelled by three-sublattices, Sb: Co, Va: Va, Co, since its structure is of the NiAs-type (B8(1)) with the Co vacancies on the Sb-rich side and the interstitial Co atoms on the Co-rich side. The compounds gamma CoSb2 and delta CoSb3 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. (C) 2007 Elsevier Ltd. All rights reserved.