Phase Equilibria in System Y2O3–SnO2

A series of samples in the Y2O3–SnO2 system with various yttrium and tin oxide ratios were synthesized using the solid-state method. The phase composition of the obtained samples was monitored by X-ray powder diffraction. The diffraction patterns were processed, and crystallographic parameters were calculated using the full-profile analysis method. The study of phase equilibria in the Y2O3–SnO2 system at 1400°C allowed first the determination of the homogeneity range of yttrium stannate Y2Sn2O7, which is shifted toward yttrium oxide and ranges from 33.3 to 36 mol % Y2O3. The existence of a solid solution based on cubic yttrium oxide extending up to 3 mol % SnO2 was established. A comparative analysis of the influence of the substituting tetravalent cation radius on the homogeneity range of the solid solution based on yttrium oxide was conducted. The absence of yttrium oxide solubility in tin dioxide was noted.