Abstract
In this experiment, vacuum hot pressing (VHP) was applied in order to get the transparent Y2O3. where LiF. NaF or NH4F was added as the sintering additive. Transparent Y2O3 was obtained by LiF addition under following UP conditions: temperature 1573K. pressure 400kgf/cm2, vacuum 10-4Torr. sintering time 2h. In the case of NaF or NH4F, however, the transparent Y2O3 was not obtained, where the residual F(fluorine) was detected by EPMA in the opaque region. Much more homogeneous structure was observed in the transparent Y2O3 than the opaque one, and it was also confirmed that the grain size is larger in the former than the latter.
