THERMODYNAMIC PROPERTIES OF LIQUID Na-Mg AND K-Mg ALLOYS.

Results of an investigation are presented which show that solutions of the Na-Mg and K-Mg systems at 700 C exhibit very large positive deviations from Raoult's law; this is due to phase separation (formation of the structures of pure components). Temperature has little influence on the magnitude of the deviations. The emf varies linearly with temperature in the region of homogeneous alloys; in the region of phase separation the temperature coefficient of emf is not constant, increasing with temperature. The solubility of sodium increases in the temperature range 638-700 C from 2. 1 to 2. 7 at. %, i. e. , by 0. 6 at. %. The maximum solubility of potassium in liquid magnesium at 700 C does not exceed 1. 0 at%. Formation of liquid Na-Mg alloys is accompanied by small endothermic effects. The values of DELTA H lies in the range 80-240 cal/g-atom and is determined mainly by the entropy term.