The 773 K Isothermal Section of the Nd—Fe—Sb Ternary System.

Abstract

Equilibria E 4000The 773 K Isothermal Section of the Nd-Fe-Sb Ternary System. -The study of the 773 K isothermal section of the phase diagram of the title system leads to the detection of two new ternary compounds, NdFeSb3 and NdFe2.5Sb2. As revealed by powder XRD, NdFeSb3 crystallizes in the orthorhombic space group Pbcm (CeNiSb3-type structure). The existence of the compounds Nd6Fe13Sb, NdFe1-xSb2, and NdFe4Sb12 is confirmed. -(ZENG*, L.; QIN, P.; NONG, L.; ZHANG, J.; LIAO, J.;

The system Nd–Fe–Sb: Phase equilibria, crystal structures and physical properties

“…Therefore due to improper choice of annealing temperature, this phase was not caught by Zeng et al [10]. s 3 is found to exist in equilibrium with three other ternary compounds s 2 , s 4 and s 5 (details in Section 3.2).…”

“…d The compound NdFeSb 3 with CeNiSb 3 type reported by [42] was not confirmed but was observed with LaPdSb 3 -type in the present work. e The compound "NdFe 2.5 Sb 2 " with unknown structure observed by [10] at 500 C is likely to refer to the orthorhombic s 2 -phase.…”

“…The ternary compounds in this composition range were reported as s 2 -NdFe 2Àx Sb 2 (orthorhombic) and NdFe 3 Sb 2 (tetragonal) [6] and more recently as wNdFe 2.5 Sb 2 (unknown structure) [10] in the isothermal section at 500 C. Whilst in the systems LaeFeeSb and PreFeeSb at 500 C, the ternary compounds LaFe 2 Sb 2 [11] and PrFe 2 Sb 2 (a ¼ 0.60719 nm, b ¼ 0.60867 nm, c ¼ 1.33051 nm, b ¼ 103.1 ) [12] were tentatively indexed as monoclinic phases with Ga 2 S 3 prototype (S.G. Cc), we were unable to index or refine the observed XRPD (mentioned above) with the Ga 2 S 3 structure type. However, the observed patterns were completely indexed on the basis of orthorhombic and tetragonal unit cells as reported by Leithe-Jasper [6] for s 2 -NdFe 2Àx Sb 2 and NdFe 3 Sb 2 , respectively.…”

“…Phase equilibria in the composition range FeeNdSbeNd are accepted after Leithe-Jasper [6]. All ternary phases reported previously, s 1 -Nd 6 Fe 13 Sb (Nd 6 Fe 13 Si-type) [6], s 2 -NdFe 2Àx Sb 2 (orthorhombic) [6], NdFe 3 Sb 2 (tetragonal) [6], wNdFe 2.5 Sb 2 (unknown type [10], this phase is likely to correspond to orthorhombic s 2 -NdFe 2Àx Sb 2 of [6]), s 3 -Nd 2 Fe 3Àx Sb 5 [6], s 4 -NdFeSb 3 [6,10], s 5 -NdFe 1Àx Sb 2 (ZrCuSi 2 -type) [30] and s 6 -NdFe 4 Sb 12 (LaFe 4 Sb 12 type) [37] were observed in the present work. The crystal structures of s 2 and s 3 have been determined by single crystal x-ray diffraction in the present work (for details see consisting of only three phases as can be seen from Fig.…”

“…Compounds isotypic to the tetragonal structure were observed with La and Ce while compounds with Pr and Sm were found isostructural to the orthorhombic structure. A more recent investigation of the NdeFeeSb system by Zeng et al [10] at 500 C showed a compound NdFe 2.5 Sb 2 with unknown structure but did not reveal s 3 -Nd 2 Fe 3Àx Sb 5 [6]. Therefore the aim of the present work is threefold: (i) to investigate phase relations in the Sbrich part of the NdeFeeSb system (region FeeNdSbeSb) in a wider temperature range, (ii) to elucidate crystal structure and formation of ternary phases (s 2, s 3 and s 4 ) including the light rare earth containing homologues, and (iii) to study their physical properties.…”