ACTIVITIES, CONCENTRATION FLUCTUATIONS AND COMPLEXING IN LIQUID Ca-Al ALLOYS.

Abstract

A knowledge of activities in liquid Ca-Al alloys is of interest in understanding the physical chemistry of aluminothermic reduction of calcium oxide in vacuum. During this process a Ca-Al alloy is formed which decreases the efficiency of utilization of Al in the reduction process. The phase diagram for the Ca-Al system shows an intermetallic phase Al//2Ca congruently melting at 1352K and Al//2Ca melting incongruently at 973 K. The intermetallic Al//2Ca has potential application as a high temperature hydrogen storage medium. Activities have been measured in this study using a combination of Knudsen effusion and distribution measurements at 1373 K.