Contribution to the investigation of the Sm–Cu–Sn ternary system

Chem. Met. Alloys 9 (2016) 72-77

https://doi.org/10.30970/cma9.0325

L. ROMAKA, V.V. ROMAKA, A. HORYN, Yu. STADNYK

The isothermal section of the phase diagram of the Sm–Cu–Sn ternary system was constructed at 870 K in the whole concentration range based on X-ray diffraction and EPM analysis. The interaction between the elements results in the formation of five ternary compounds at this temperature: SmCuSn (NdPtSb-type), Sm₃Cu₄Sn₄ (Gd₃Cu₄Ge₄-type), SmCu₅Sn (CeCu₅Au-type), Sm_1.9Cu_9.2Sn_2.8 (related to CeNi₅Sn-type), and SmCu₂Sn₂ (CaBe₂Ge₂-type). DSC analyses showed a limited stability range for the Sm₂Cu₄Sn₅ compound (up to 811 K), as well as for the isotypic R₂Cu_4-xSn_5+x compounds with Pr (496-783 K) and Nd (671-791 K). Rietveld refinement of the crystal structure of SmCu₅Sn confirmed CeCu₅Au-type atom ordering (space group Pnma, a = 0.8267(1), b = 0.50087(6), c = 1.0601(1) nm).

Isothermal section of the Sm–Cu–Sn system at 870 K.

Keywords

Intermetallics / Phase diagrams / X-ray diffraction / Rare earth metal system