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, p, 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 p and decrease of the temperature coefficient of p, dp/dT were found in the homogeneous liquid phase of liquid Bi-Ga and Cd-Ga alloys. However, increase of p and decrease of dp/dT were observed for the liquid Hg-Ga system. Both tendencies were explained successfully by the concentration fluctuation model. The rocket experiment for the p of liquid Bi-Ga alloys revealed that, under microgravity, the concentration fluctuation grows extensively and the nucleation for TLPS is suppressed.