Page 115 - International Space Station Benefits for Humanity, 3rd edition.

The Japan Aerospace Exploration Agency (JAXA) has and crystallized it through supercooling. As a result,
been developing this technique on Earth for more than we succeeded in developing a high-performance
20 years. In 2015, JAXA completed the development material that has a huge dielectric constant and is
of the Electrostatic Levitation Furnace (ELF) for the ISS. unaffected by temperature changes.
The ELF is a facility for material science that melts In 2018, the initial checkout of the ELF was completed
levitating materials having a very high melting point, onboard Kibo, which included the density measurement
measures their properties, and solidifies them from of molten alumina, and the ELF experiment finally
a supercooled state by taking advantage of the began. ISS-ELF can measure the thermophysical
microgravity environment. The main target sample properties (i.e., density, surface tension and viscosity)
of the ISS mission is oxides. The melt oxides cannot of high-temperature melts above 2000°C (3632°F).
be levitated by electromagnetic force, and it is difficult (Tamaru, H. et al., 2018, https://doi.org/10.1007/
to do so by electrostatic levitator on the ground s12217-018-9631-8).
because the electric charge of nonconductors is
much less than that of conductors. The thermophysical properties data of materials at a
high temperature is useful for the study of liquid states
The techniques of measuring the thermophysical and the improvement of numerical simulation by
properties of high-temperature melts were improved modeling the manufacturing processes using the liquid
with a ground-based facility during the preparatory state as the basic data for computer-based casting
research for the ELF on Kibo. Many thermophysical technology to be applied to efficient turbines for electric
properties of refractory metals have been revealed for generation systems, aircraft, and the next generation
the first time. Moreover, containerless processing can of jet engines. Moreover, the interfacial energy
provide a large, supercooled state that allows for the of immiscible melts will be measured by creating
formation of different crystalline structures and phases a core-shell droplet configuration, which otherwise
from which new materials can be created. cannot be obtained on the ground due to
We levitated and melted barium titanate (BaTiO3) sedimentation.
without a crucible during a ground-based experiment,
The ELF technology will dramatically improve the quality
of the fundamental data of material science by the
thermophysical data acquired onboard Kibo. We also
expect to find unknown characteristics of materials
through crystallization using containerless processing.

The ground-based electrostatic levitator.
Controlling the sample position using Coulomb Molten alumina levitating in the center of six
force between charged samples and electrodes. electrodes onboard the ISS.
Image credit: JAXA Image credit: JAXA

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