Phase analysis of Gd5(Si xGe1-x)4 alloys prepared from different purity Gd with x = 0.475 and 0.43

The magnetocaloric effect materials Gd5(Si xGe1-x)4 with x = 0.475 and 0.43 based on 99.94 wt% and 99.2 wt% purity Gd have been synthesized and their phase components have been investigated by X-ray diffraction, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). According to the X-ray powder diffraction analysis, Gd5Si1.9Ge2.1 with high purity Gd is Gd5Si2Ge2-type single-phase, whereas Gd5Si1.72Ge2.28 with high purity Gd presents Gd5Si2Ge2-type and GdGe-type phases. On the other hand, Gd5Si2Ge2-type, Gd5Si3-type, and GdGe-type multi-phases have been found in both Gd5Si1.9Ge2.1 and Gd5Si1.72Ge2.28 with low purity Gd. In addition, SEM clearly shows the three discernible phases in the alloys with low purity Gd; EDS analyses have been conducted on all of them