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

Abstract

Abstract 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 Ce 24 Co 11 , CeCo 2 , CeCo 3 , Ce 2 Co 7 , Ce 5 Co 19 , Ce 2 Co 17 , CoSb, CoSb 2 , CoSb 3 , Ce 2 Sb, Ce 5 Sb 3 , Ce 4 Sb 3 , CeSb and CeSb 2 have been confirmed, and three ternary compounds CeCoSb 3 , CeCo 1− x Sb 2 and CeCo 1.33 Sb 2 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 CeCo 1− x Sb 2 has ZrCuSi 2 -type structure with space group P 4/ nmm , a = 0.3878 nm and c = 0.9849 nm. The crystal structure for the compound CeCoSb 3 is determined to be CeNiSb 3 -type ( Pbcm ) with a = 1.27697 nm, b = 0.60601 nm and c = 1.8435 nm. The compound CeCo 1.33 Sb 2 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.