Determining the density of molten Y2O3 using an electrostatic levitation furnace in the International Space Station

This work employed the electrostatic levitation furnace (ELF) apparatus installed in the KIBO Japanese Experiment Module on the International Space Station. The ELF is able to levitate high-melting-point materials such as ceramics without containers. The heating and melting of refrac-tory oxides in this apparatus allows the analysis of various thermophysical properties, including density, surface tension and viscosity, that are other-wise very difficult to measure in terrestrial laboratories. In the present study, the density of molten Y2O3 was determined over a wide temperature range using the ELF. A density of 4700 kg/m3 was obtained at 2712 K, in good agreement with the value previously obtained using an aero-acoustic levitator. The relationship between the ionic radius and the molar volume of liquid Y2O3 was ascertained and found to be similar to those for other non-glass-forming sesquioxides.