Isothermal section of the Ho–Cu–Sn ternary system at 670 K

L. Romaka,Yu. Stadnyk,A. Horyn,M. Konyk,V. Romaka,I. Romaniv

doi:10.15330/pcss.19.2.139-146

Abstract

The interaction of the components in the Ho-Cu-Sn ternary system was investigated at 670 K over the whole concentration range using X-ray diffraction and EPM analyses. Four ternary compounds were formed in the Ho–Cu–Sn system at 670 K: HoCuSn (LiGaGe type, space group P63mc), Ho3Cu4Sn4 (Gd3Cu4Ge4-type, space group Immm), HoCu5Sn (CeCu5Au-type, space group Pnma), and Ho1.9Cu9.2Sn2.8 (Dy1.9Cu9.2Sn2.8-type, space group P63/mmc). The formation of the interstitial solid solution based on HoSn2 (ZrSi2-type) binary compound up to 5 at. % Cu was found.

Highlights

Among R-M-Sn systems (R- rare earth element, Md-element) the ternary systems with rare earth metals, copper and tin were studied with the most rare earths [114] and are characterized by a large variety of stoichiometry and crystal structures of the intermediate ternary phases
An analysis of previously studied R–Cu–Sn systems with light rare earths and heavy rare earth elements indicated the significant influence of f-element on the formation, chemical and structural characteristics of intermediate ternary phases
Phase equilibria in the Ho-Cu-Sn system have been studied using X-ray analysis and scanning electron microscopy of 15 binary and 29 ternary alloys annealed at 670 K (Fig. 1)

Summary

Introduction

Among R-M-Sn systems (R- rare earth element, Md-element) the ternary systems with rare earth metals, copper and tin were studied with the most rare earths [114] and are characterized by a large variety of stoichiometry and crystal structures of the intermediate ternary phases. An analysis of previously studied R–Cu–Sn systems with light rare earths and heavy rare earth elements indicated the significant influence of f-element on the formation, chemical and structural characteristics of intermediate ternary phases. Previous investigations of the R-Cu-Sn ternary systems with rare earths of Yttrium group (R = Y, Gd, Dy, Er, Lu) [1, 9,10,11, 14] showed the quite decreasing number of formed compounds up to three for the Lu-Cu-Sn system, excepting the Yb-Cu-Sn system where ten intermediate phases were found at 673 K [13]. In the Cu-rich corner of R-Cu-Sn systems the formation of the RCu5Sn compounds (except “LuCu5Sn” phase in the Lu-Cu-Sn system) and R1.9Cu9.2Sn2.8 (R=Y, Ce-Nd, Sm, Gd-Lu) was observed. Ho30Cu55Sn15 (HoCuSn–grey light phase, HoCu5-xSnx –grey phase, HoCu2–dark phase); b) 5. (Ho1.9Cu9.2Sn2.8–grey phase, HoCuSn–grey light phase, Cu3Sn–dark phase)

Ho Cu Sn

Space group Structure type

Results

Pnma а

Final remarks