The ternary Eu-Cu-Si system at 400°C

Abstract

Based on X-ray diffraction and microstructure analysis the isothermal section at 400°C of the phase diagram of the system Eu-Cu-Si was built. The compound EuCu 2 Si 2 (CeAl 2 Ga 2 structure type) was confirmed and its homogeneity region was determined (EuCu 2.25-1.50 Si 1.75-2.50). The compound EuCu 0.80-0.20 Si 1.20-1.80 (AlB 2 structure type) is also characterized by a variable content of copper and silicon. In addition, four new compounds with unknown structure were found in this system. The effective valence of europium was studied.

The ternary system Eu–Cu–Ge at 400°C

“…It may be mentioned that also the structure type HoNiGa, observed at the equiatomic composition, can be derived from the AlB 2 type by substitution and deformation [27]. The volume per formula unit for EuCuGe, 0.0606 nm 3 , falls approximately on the line formed by the other RCuGe compounds.…”

“…The compound EuCu 5 melts congruently at 847°C, whereas EuCu 2 , EuCu, and Eu 2 Cu form via peritectic reactions at 597, 537, and 442°C, respectively. In [3] it was noted that the binary compound EuCu 5 has a certain homogeneity range. Five binary compounds were found during an investigation of the binary system Eu-Ge [4].…”