Chemical partitioning for the Co–Pr system: First-principles, experiments and energetic calculations to investigate the hard magnetic phase

Abstract

Co5Pr-D2d is promising permanent magnet. Due to its peritectic formation feature, there is a synthetic challenge to produce single Co5Pr-D2d phase. The object of this study is to assess thermodynamic pathways for crystalline phases under far-from-equilibrium conditions by combining first-principles calculations and experimental measurements into a robust description of the thermodynamic behavior. With the energetic calculations, temperature and time dependent phase selections are predicted under varying degrees of chemical partitioning. Our calculation to assess the chemical partitioning-temperatures indicates that the major magnetic compounds: Co17Pr2-, Co5Pr-D2d, Co19Pr5-, and Co7Pr2- form from a congruent manner to eutectic reactions with decreasing cooling rate. The compositions of the compounds from these highly driven liquids can be far from equilibrium.

Thermodynamic database for the Co-Pr system

“…Thermodynamic database was assessed with all relevant experimental and first-principles calculations. The database in TDB format can be used to thermodynamic properties, phase diagram and Chemical Partitioning-Temperature-Phase Transformation calculation [4] .…”