Phase relationships in the Pr–Fe–Sb system at 773 K

The isothermal section of the phase diagram of the Pr–Fe–Sb ternary system at 773 K has been investigated mainly by X-ray powder diffraction with the aid of metallographic analysis. Four ternary compounds Fe4PrSb12, FePrSb2, Fe13Pr6Sb and FePrSb3 have been confirmed and a new ternary compound PrFe2Sb2 was found in this system at 773 K. The isothermal section consists of 16 single-phase regions, 33 two-phase regions and 19 three-phase regions.The homogeneity range of ɛ (FeSb) phase extended from about 44 at.% Sb to 46 at.% Sb. The solubilities for the other single-phase regions were not observed. The structure type for PrFe2Sb2 is Ga2S3-type (sp. gr. Cc (no. 9), a = 0.60719 nm, b = 0.60867 nm, c = 1.33051 nm, β=103.1°).