The isothermal section of the Nd–Fe–Ga ternary system at 773 K

Abstract

The isothermal section of the Nd–Fe–Ga ternary system at 773 K was constructed using X-ray diffraction analysis. Ten binary compounds, Nd 2Fe 17, Nd 5Fe 17, Nd 9Ga 4, Nd 5Ga 3, NdGa, NdGa 2, FeGa 3, Fe 3Ga 4, α-Fe 6Ga 5 and α-Fe 3Ga, and three ternary compounds, NdFe 2Ga 8, NdFe 5Ga 7 and Nd 6Fe 13Ga were existed in this isothermal section. The solid solutions Nd 2Fe 17.00–15.57Ga 0–1.43 (Th 2Zn 17-type structure, space group R 3 ¯ m ), NdFe 5.46–4.65Ga 6.54–7.35 (ThMn 12-type structure, space group I4/ mmm) and Nd 6Fe 13.0–12.0Ga 1.0–2.0 (La 6Co 11Ga 3-type structure, space group I4/ mcm) were formed by substitution of Ga for Fe in the compounds Nd 2Fe 17, NdFe 5Ga 7 and Nd 6Fe 13Ga at 773 K, respectively. The ternary compound NdFe 2Ga 8 is CaCo 2Al 8-type (space group Pbam) with a = 1.43742 (4), b = 1.24601 (4), c = 0.40479 (1)). The homogeneity range of NdGa 2 is from 66.7 to 74.7 at.% Ga in Nd–Ga side but the solid solubility of Fe in this compound is very small. The homogeneity ranges of Nd 6Fe 13Ga and NdFe 5Ga 7 are from 5.0 to 10.0 and from 50.3 to 56.5 at.% Ga, respectively. The maximum solid solubilities of Ga in Nd 2Fe 17 is 7.5. The homogeneity ranges for the other compounds are small.