Thermophysical properties of molten Ga₂O₃ by using the electrostatic levitation furnace in the International Space Station

Abstract

We measured thermophysical properties of molten gallium oxide (Ga2O3) in a contamination-free and microgravity environment by using the electrostatic levitation furnace in the International Space Station. The density of molten Ga2O3 was obtained over a wide temperature range of 2001-2174 K including the undercooled state and found to be expressed as 5004.8 – 0.4478(T − Tm) (kg/m3), where Tm, the melting point, is 2066 K. Measurements of its viscosity and surface tension were also performed by using the oscillating drop method and these values were found to be 337.0 (10-3 N/m) and 13.6 (10-3 Pa∙s) at 2228 K, respectively

Density measurements of molten Y3Al5O12 and Y2O3‐Al2O3 compounds using an electrostatic levitation technique

“…Densities of molten compounds were measured by ESL. Density of Y 2 O 3 was already measured by Electrostatic Levitation Furnace onboard the International Space Station (ISS‐ELF), 21 and was adopted in this paper. As mentioned at the beginning of this discussion section, densities of Al 2 O 3 were also measured by both ESL 18 and ISS‐ELF 14 .…”

“…With the exception of the Y 2 O 3 , 21 all samples were deeply undercooled, and densities were ascertained over a wide temperature range. In contrast, the Y 2 O 3 was found to crystalize near its melting temperature such that the density of this compound could not be measured in the undercooled region.…”

Electrical and Gas Sensor Properties of Nb(V) Doped Nanocrystalline β-Ga2O3

“…It should be noted that at 1000 • C annealing temperature, specific surface area value sharply decreases. This effect is probably connected with formation of GaNbO 4 phase on particle surface: lower melting temperature of GaNbO 4 (below 1700 K) [39] in comparison to Ga 2 O 3 (above 2000 K) [40] leads to higher ion mobility and enhancement of diffusion processes.…”

The surface tension of Ga2O3 melt measured by a drop-weight method in an optical floating-zone furnace

“…The Ga 2 O 3 melt is easily decomposed and contaminated by a crucible at high temperature (melting point = 2093 K), making measurements using conventional methods, such as sessile drop [19] and maximum bubble pressure, difficult [20,21]. In recent years, researchers have developed containerless techniques to measure the surface tension of molten oxides, including aerodynamic levitation [22,23], electrostatic levitation [24], and the pendant droplet (PD) method based on a thermal imaging furnace [25]. These methods can solve the above-mentioned problems to a certain extent, but often have higher requirements for the equipment and experimental environment, such as a high-precision imaging system or even microgravity environments.…”