Measurement of zinc activity in the ternary In-Zn-Sn alloys by EMF method

Abstract

Activity of zinc in liquid In-Zn-Sn alloys has been measured by electrochemical technique based on molten salt electrolyte galvanic cell in the temperature range 753-853 K along three ternary sections of Zn x(InySn1-y)1-x where y = 0.67, 0.50 and 0.33. The activity of indium in In-Sn binary alloys has also been measured by the same technique in the same temperature range. The activity of Zinc in In-Zn-Sn alloys shows positive deviation from the Raoult's law over entire range of composition. The activity of indium in In-Sn alloys shows negative deviations from ideality for entire composition. The excess molar free energies have been computed by the Darken's treatment of the ternary solutions using In-Sn binary data and ternary data in this study. Isoactivity curves at 813 K in the ternary In-Zn-Sn alloys were derived by combining the activity data of In-Zn and Sn-Zn alloys. The values of excess molar free energy in this study are in good agreement with those calculated from the general model calculation proposed by Chou. © 2013 Elsevier B.V.