Properties of Yttrium Oxide Ceramics

TLDR: The cubic structure of yttrium oxide is stable to 1800°C in air as indicated by petrographic, X-ray, and differential thermal analyses as mentioned in this paper, and a change in lattice parameter of less than ± 0.007 a.u.

Abstract: The cubic structure of yttrium oxide is stable to 1800°C. in air as indicated by petrographic, X-ray, and differential thermal analyses. A change in lattice parameter of less than ±0.007 a.u. was observed on heating the oxide to 1800°C. The mean specific heat of Y2O3 to 1600°C. was 0.13 cal. per gm. per °C. The coefficient of linear expansion to 1400°C. was 9.3 × 10−6 in. per in. per °C. Compacts of Y2O3 required a temperature of 1800°C. for vitrification. In equimolecular binary mixtures heated in the powdered state at 1500°C., Y2O3 formed compounds with Al2O3 and Fe2O3 and solid solutions with ZrO2 and HfO2. Y2O3 did not react with CaO, MgO, or ThO2. Crystal types and unit-cell sizes of the reaction products are included.