The ternary system Eu–Cu–Ge at 400°C

Chem. Met. Alloys 8 (2015) 63-68

https://doi.org/10.30970/cma8.0313

Bohdana BELAN, Mykola MANYAKO, Svitlana PUKAS, Roman GLADYSHEVSKII

The isothermal section at 400°C of the phase diagram of the system Eu–Cu–Ge was built based on X-ray diffraction and microstructure analysis. The compound EuCu₂Ge₂ (CeAl₂Ga₂-type structure) was confirmed and its homogeneity region was determined: EuCu_2.5-1.65Ge_1.5-2.35. In addition, three other ternary compounds were found: EuCuGe (HoNiGa-type structure), EuCu_0.8-0.5Ge_1.2-1.5 (AlB₂-type structure), and ~Eu₂Cu₂Ge (unknown structure). The effective valence of Eu in EuCu_0.8Ge_1.2 was found to be 2+. The existence of a binary homogeneity range Eu_1-xCu_5+2x was confirmed by complete structure refinements.

Isothermal section of the phase diagram of the Eu–Cu–Ge system at 400°C.

Keywords

Phase diagram / Crystal structure / Effective valence