The critical behaviour under microgravity of liquid alloys with mutual immiscibility

Abstract

The process of two-liquid phase separation (TLPS) was studied by the electrical resistivity, ρ, both on the ground and under microgravity obtained on board the sounding rocket. On cooling to the critical temperature, Tc, on the ground, increase of ρ and decrease of the temperature coefficient of ρ, dρ/dT were found in the homogeneous liquid phase of liquid Bi–Ga and Cd–Ga alloys. However, increase of ρ and decrease of dρ/dT were observed for the liquid Hg–Ga system. Both tendencies were explained successfully by the concentration fluctuation model. The rocket experiment for the ρ of liquid Bi–Ga alloys revealed that, under microgravity, the concentration fluctuation grows extensively and the nucleation for TLPS is suppressed.

Thermophysical property measurements of high temperature melts: results from the development and utilization of space

“…Holland-Moritz proposed a new electromagnetic levitator to observe the shortrange order of undercooled metallic melts [28]. Itami et al discussed concentration fluctuations in an immiscible system through electrical conductivity measurement [29].…”

The estimation of concentration fluctuations in liquid Ag–Si and Au–Si alloys

“…The concentration fluctuations may be observed sensitively by microscopic probes, such as SANS, electrical resistivity, compared with the thermodynamic ones, the specific heat, magnetic susceptibility, etc., which has been adopted conventionally for the study of critical phenomena. In addition, under microgravity, such a concentration fluctuation exists in a considerably wide temperature range [12,13]. The problem, wider fluctuation range, must be discussed further in future.…”