Subsolidus phase relationships in the Al2O3-SnO2-ZnO ternary system at 1200 °C in air

We report the subsolidus phase relationships in the Al2O3-SnO2-ZnO ternary system at 1200 °C in air. The phases and lattice parameters of samples were analyzed by powder X-ray diffraction (XRD). Only one type of solid solutions was found in this ternary system, which is Al-substituted zinc stannate spinel ternary compounds of Zn2-xSn1-xAl2xO4-type solid solutions with the solubility limit of x ≈ 0.045 at 1200 °C in air. In comparison with In2O3-SnO2-ZnO and Ga2O3-SnO2-ZnO ternary systems previously reported, the solubility limit of Al3+ (≈4.5 mol %) in the Zn2-xSn1-xAl2xO4-type solid solution is much smaller than those of In3+ and Ga3+ in Zn2SnO4 for the substitution of the Sn4+ site, where In3+ and Ga3+ solubility limits are 90 and 100 mol % at 1275 °C and 1250 °C, respectively, in air. In addition, unlike previous report, no solid solution was found to exist more than 0.5 mol% of Zn2+ in Al2O3 at 1200 °C in air. On the basis of our experimental data, we were able to construct the subsolidus phase diagram of the Al2O3-SnO2-ZnO ternary system at 1200 °C in air.