Experimental study on gallium activity in the liquid Ga-In-Tl alloys by EMF method with zirconia solid electrolyte

EMF of galvanic cells with zirconia solid electrolytes was measured to determine the activity of gallium in liquid Ga-In-Tl alloys in the temperature range of 950-1300 K along three pseudo-binary lines of (InyTl1 − y)-Ga where y = 0.25, 0.50 and 0.75. A mixture of Ga and Ga2O3 was used as a reference electrode. The activity curves of Ga show positive deviations from ideality in the whole composition range. Isoactivity curves at 1073 K in the ternary Ga-In-Tl alloys were derived by combining the activity data of Ga-In and Ga-Tl alloys. Excess free energy of mixing ΔGEx(=ΔG − ΔGideal) at 1073 K was derived by Darken's equation using the binary data of In-Tl and ternary data in this study. The values in this study are smaller than those calculated from the general model calculation proposed by Chou.