Thermodynamic optimization of Bi-Ni binary system
(1. School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin 541004, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
3. Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Joining and Interface Technology, Überlandstrasse 129, CH-8600, Dübendorf, Switzerland;
4. School of Materials Science and Engineering, Central South University of Forestry and Technology,
Changsha 410004, China)
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
3. Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Joining and Interface Technology, Überlandstrasse 129, CH-8600, Dübendorf, Switzerland;
4. School of Materials Science and Engineering, Central South University of Forestry and Technology,
Changsha 410004, China)
Abstract: Based on the available experimental data, the Bi-Ni binary system was optimized thermodynamically by the CALPHAD method. The solution phases, including liquid, fcc_A1(Ni) and rhombohedral_A7(Bi), were described as substitutional solution phases, of which the excess Gibbs energies were expressed with the Redlich-Kister polynomial. The intermetallic compound, BiNi, was modeled using three sublattices (Bi)(Ni,Va)(Ni,Va) considering its crystal structure (NiAs-type) and the compatibility of thermodynamic database in the multi-component systems, while Bi3Ni was treated as a stoichiometric compound. Finally, a set of self-consistent thermodynamic parameters formulating the Gibbs energies of various phases in this binary system were obtained. The calculated results are in reasonable agreement with the reported experimental data.
Key words: Sn-based alloy; phase diagram; thermodynamics; CALPHAD; Bi-Ni binary system