Phase equilibria of the Ag–Gd–Sn ternary system at 400 °C

The isothermal section at 400 °C in the Ag–Gd–Sn system was established by means of X-ray diffraction, optical microscope, and scanning electron microscope with energy dispersive spectroscope. The existence of two ternary compounds, hexagonal-AgGdSn and orthorhombic-Gd3Ag4Sn4, was confirmed. The lattice parameter of Gd3Ag4Sn4 was refined to be a = 1.52199(6), b = 0.73057(3) and c = 0.45656(2) nm. The existence of Gd5Sn3, Gd5Sn4, Gd11Sn10, GdSn2, Gd3Sn7, Ag51Gd14, Ag2Gd, AgGd, Ag3Sn and Ag4Sn binary phases was also confirmed in the present work. Gd11Sn10 was observed to crystallize in the Ho11Ge10 type structure. Neither Gd8Sn7 nor Gd3Sn was observed in the Gd–Sn binary system. Results of X-ray diffraction suggest that Gd3Sn4 might exist. XRD revealed that Gd(AgSn)3 substituted solution rather than GdAgSn2 ternary compound exists in Ag–Gd–Sn system. The maximum solubility of Ag in GdSn3, and those of Sn in AgGd2 and Ag51Gd14 are measured to be about 12, 5 and 4 at.%, respectively.