The isothermal section of the Ce–Co–Sb ternary system at 400 °C

Phase equilibria were established in the Ce–Co–Sb ternary system at 400 °C based on X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) techniques. Fourteen binary compounds Ce24Co11, CeCo2, CeCo3, Ce2Co7, Ce5Co19, Ce2Co17, CoSb, CoSb2, CoSb3, Ce2Sb, Ce5Sb3, Ce4Sb3, CeSb and CeSb2 have been confirmed, and three ternary compounds CeCoSb3, CeCo1−xSb2 and CeCo1.33Sb2 are found in this system at 400 °C. The isothermal section of this system at 400 °C consists of 20 single-phase regions, 40 two-phase regions and 21 three-phase regions. The compound CeCo1−xSb2 has ZrCuSi2-type structure with space group P4/nmm, a = 0.3878 nm and c = 0.9849 nm. The crystal structure for the compound CeCoSb3 is determined to be CeNiSb3-type (Pbcm) with a = 1.27697 nm, b = 0.60601 nm and c = 1.8435 nm. The compound CeCo1.33Sb2 is of orthorhombic system with a = 0.6083 nm, b = 0.60118 nm and c = 1.04596 nm. The homogeneity range of CoSb phase is about 2 at.%. The solubilities for the other single-phase regions were not observed.