Thermodynamic Description of Ternary Fe-X-P Systems. Part 8: Fe-Si-P

Thermodynamic descriptions of the Fe-Si-P system is developed in the frame of a new Fe-X-P (X = Al, Cr, Cu, Mn, Mo, Si, Ni, Si, Ti) database. The thermodynamic parameters of the binary sub-systems, Fe-Si, Fe-P and Si-P, are taken from the earlier assessments and those of the Fe-Si-P system are optimized in this study using the experimental thermodynamic and phase equilibrium data of the literature. The solution phases of the system (bcc_A2, fcc_A1, dia_A4, liquid) are described with the substitutional solution model. The compounds are treated either with the sublattice model (FeSi₂-H, Fe₂P and FeP) either as stoichiometric phases (Fe₃P, Fe₂Si, Fe₅Si₃, FeSi, FeSi₂-L, SiP, SiP₂ and FeSi₄P₄). No solubility of Fe neither Si in the white P-phase has been modeled. The correlation between the calculated and the experimental thermodynamic and phase equilibrium data is reasonably good.