Phase diagrams of the RE （rare earth）-Ⅳ-Ⅵ systems are very important for the design of rare earth doped diluted magnetic semiconductors （DMSs）, but related information is very limited. In this work, the phase equilibria of the Er-Sn-Te system in whole compositional range at room temperature were investigated mainly by means of X-ray powder diffraction （XRD） and differential thermal analysis （DTA）. The existences of 9 binary compounds, i.e., SnTe, ErTe3, EraTe3, ErTe, ErsSn3, Er11Sn10, ErSn2, Er3Sn7 and Er2Sn5 were confirmed. The phase diagram consisted of 12 single-phase regions, 21 binary phase regions and 10 ternary phase re- gions. The maximum solid solubility of Er in SnTe was determined to be about 7.5 at.%, none of the other phases in this system re- vealed a remarkable homogeneity range at room temperature. No ternary compound was found in this work.
The isothermal section of the Nb-Y-Si ternary system at 873 K was investigated over the whole concentration range mainly by powder X-ray diffraction （XRD）, scanning electron microscopy （SEM） and energy dispersive analysis （EDX）. This isothermal section con- sisted of 10 single-phase regions, 17 two-phase regions, and 8 three-phase regions. The existence of the binary compounds, i.e., Y5Si3, Y5Si4, YSi, Y3Sis, YSi〉 NbsSi3 and NbSi2 at 873 K was confirmed. On the basis of XRD patterns, the structure types of Y3Si4, Y3Si5 and YSi2 were discussed. No ternary compound and no detectable solid solubility in the binary compounds were found.
