The critical behaviour under microgravity of liquid alloys with mutual immiscibility

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, T c , on the ground, increase of ρ and decrease of the temperature coefficient of ρ, dρ/d T were found in the homogeneous liquid phase of liquid Bi–Ga and Cd–Ga alloys. However, increase of ρ and decrease of dρ/d T 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.