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

The isothermal section of the Nd–Fe–Ga ternary system at 773 K was constructed using X-ray diffraction analysis. Ten binary compounds, Nd2Fe17, Nd5Fe17, Nd9Ga4, Nd5Ga3, NdGa, NdGa2, FeGa3, Fe3Ga4, α-Fe6Ga5 and α-Fe3Ga, and three ternary compounds, NdFe2Ga8, NdFe5Ga7 and Nd6Fe13Ga were existed in this isothermal section. The solid solutions Nd2Fe17.00–15.57Ga0–1.43 (Th2Zn17-type structure, space group R 3 ¯ m ), NdFe5.46–4.65Ga6.54–7.35 (ThMn12-type structure, space group I4/mmm) and Nd6Fe13.0–12.0Ga1.0–2.0 (La6Co11Ga3-type structure, space group I4/mcm) were formed by substitution of Ga for Fe in the compounds Nd2Fe17, NdFe5Ga7 and Nd6Fe13Ga at 773 K, respectively. The ternary compound NdFe2Ga8 is CaCo2Al8-type (space group Pbam) with a = 1.43742 (4), b = 1.24601 (4), c = 0.40479 (1)). The homogeneity range of NdGa2 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 Nd6Fe13Ga and NdFe5Ga7 are from 5.0 to 10.0 and from 50.3 to 56.5 at.% Ga, respectively. The maximum solid solubilities of Ga in Nd2Fe17 is 7.5. The homogeneity ranges for the other compounds are small.