An investigation of the Gd-Fe-Cr phase diagram: Phase equilibria at 800 °C

Abstract The phase equilibria of Gd-Fe-Cr system were investigated at 800 °C by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The isothermal section of the phase diagram consisted of eight single-phase regions, eight two-phase regions and seven three-phase regions. The binary compounds GdFe 2 , GdFe 3 , Gd 2 Fe 17 , σ (FeCr) and the ternary compound GdFe 10 Cr 2 were confirmed. Conversely, the binary compound Gd 6 Fe 23 was unstable at the level of 800 °C. The maximum solid solubilities of Cr in GdFe 2 and Gd 2 Fe 17 were about 11.7 and 13.2 at. % Cr respectively. The compound GdFe 12− x Cr x with the ThMn 12 -type structure (space group I 4 / m m m ) has a broad solubility ranging from 15.4 to 23.1 at. % Cr.