Abstract
Containerless solidification processes in undercooled Lu2O3 and Y2O3 melts were investigated using an aerodynamic levitation furnace and a high-speed video. Double recalescence, indicative of two successive phase transitions, was observed for both oxides. The melting point following the first recalescence (T M1) was higher than that of the second (T M2) for Y2O3, which suggests that Y2O3 has a phase transition from a melt to a high temperature phase at T M1, and then to a room temperature phase at T M2. Two solid phases of Lu2O3 were also identified at T M1 and T M2. However, in contrast to Y2O3, T M1 was lower than T M2 for Lu2O3. This implies that the first crystallized phase from a melt is a metastable phase. The life duration of this metastable Lu2O3 was in the order of tens of milliseconds.