On the binary Sb–Sn system: ab initio calculation and thermodynamic remodeling

The thermodynamic descriptions of phase diagrams play an important role in modern materials engineering, especially as a part of materials genome used for development of new alloys. Therefore, it is crucial to have a thermodynamic database that is in agreement with recent experimental findings. The binary Sb–Sn system is an important part of step soldering and a promising Li-ion battery electrode; therefore, a knowledge of its phase equilibria is essential for modern engineering. The newest experimental results enhanced the knowledge about phase equilibria and crystal structures in this system, and hence it is possible to propose a new, more accurate thermodynamic model of this important binary system. In this work, the CALPHAD method was used for determination of Gibbs energies of all phases; moreover, the new knowledge about a crystal structure of intermetallic compound Sb3Sn4 enabled the application of the first-principles calculations, which made CALPHAD description more precise. The proposed thermodynamic description shows a good agreement with available experimental data and can be used for future development of higher-ordered alloys.