Experimental phase equilibria of the Mg–Sn–Ce ternary system at 800 K

Abstract

The phase equilibria of the Mg–Sn–Ce ternary system at 800 K were investigated by means of X-ray powder diffraction (XRD) and scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS). Six stable ternary phases (τ1-τ6) and one suspected ternary compound (A2) were observed in the section. Three known ternary compounds τ1 (MgSnCe, Pnma, oP12), τ2 (MgSn2Ce, I-42m, tI32) and τ3 (Mg23SnCe6, Fm-3m, cF120) were confirmed at 800 K. The new ternary phase τ4 (Mg40+4Sn26–4Ce34) has the iso-structure of Mg3·9Sn2·1La3 (Cu4Si2Zr3 prototype, P-62m, hP9). The crystal structures of the two additional new ternary compounds τ5 (Mg44Sn34Ce22) and τ6 (Mg40Sn36Ce24) have not been determined. It has not been identified that A2 (Mg10Sn39Ce51) is a ternary compound or a Ce–Sn binary compound with a solubility of Mg. CeSn3, Ce3Sn5, αCe5Sn3 and Ce3Sn were detected to contain solubility of Mg as 13.6, 1.0, 2.0 and 2.7 at.%, respectively. The Mg3Ce and MgCe contain small solubility of Sn as 1.0 and 4.5 at.% Sn. The tie-triangles of the ternary system have been identified.