First-Principle Calculation Assisted Thermodynamic Assessment of the Pt-Pb System

Thermodynamic assessment of the Pt-Pb binary system has been performed by combining first-principle calculations with the CALPHAD method. The formation enthalpies of the Pt₃Pb and PtPb₄ were calculated by using the projector-augmented-wave (PAW) method within the generalized gradient approximation (GGA). The CALPHAD assessment of the Pt-Pb system was then performed. The solution phases (liquid and fcc) were treated as substitutional solutions, the excess Gibbs energies of which were modeled using the Redlich-Kister polynomial. The three intermetallic compounds, Pt₃Pb, PtPb, and PtPb₄, were described as stoichiometric phases. Thermodynamic parameters of all the phases were optimized, which reproduces the most experimental data.