Thermodynamic description of the Er–Fe–Sb system

The Er–Fe, Er–Sb and Er–Fe–Sb systems were optimized by means of the CALPHAD (CALculation of PHAse Diagram) technique. The solution phases, liquid, bcc, fcc, hcp and rhom, were described by the substitutional solution model. The binary compounds, Er2Fe17, Er6Fe23, ErFe3, ErFe2, Er5Sb3, αErSb, βErSb, ErSb2 and ternary compound Er6FeSb2 were treated as stoichiometric compounds. The thermodynamic description of the Fe–Sb system was taken from the literature. A self-consistent thermodynamic description of the Er–Fe–Sb system was obtained.

► The Er–Fe, Er–Sb and Er–Fe–Sb systems were optimized by means of the CALPHAD technique.
► The solution phases were described by the substitutional solution model.
► The compound FeSb was treated by a three-sublattice model (Fe,V a)1/3(Fe,V a)1/3(Sb)1/3.
► The compounds Er2Fe17, Er6Fe23, ErFe3, ErFe2, Er5Sb3, αErSb, βErSb, ErSb2, FeSb2 and ternary compound Er6FeSb2 were treated as stoichiometric compounds.
► A self-consistent thermodynamic description of the Er–Fe–Sb system was obtained.