Activities of Liquid Silver-Indium Alloys by E.M.F. Measurements Using Zirconia Solid and Fused Salt Electrolytes

Abstract

The E.M.F. of the galvanic cells involving zirconia solid and fused salt electrolytes have been measured in order to obtain the standard free energy of formation of In₂O₃ in the temperature range 835 to 1272 K and the thermodynamic data of the liquid Ag-In system, for N_In=0.20∼0.85 and N_In=0.25∼0.85, in the temperature ranges 925 to 1296 K and 975 to 1223 K, respectively.
The standard free energy of formation of In₂O₃ was determined as the following equation:
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Activities of indium show both positive and negative deviations from Raoult’s law, depend on the concentration of indium and they agree well with the data measured by Mycielska et al. and the others but differ from that of Nozaki et al. Activities of silver exhibit negative deviations from Raoult’s law over the whole concentration range.
The properties of liquid alloys composed of IB (Cu, Ag, Au, noble metals) and indium have been investigated from the standpoint of the alloy solution theory of Engle.
It is shown phenomenologically that the activities and ξ functions in liquid IB metals-indium alloys are better accounted for if the filling of the d shell is placed between IB metals and indium leaving copper, silver and gold as transition metals.
The activities of liquid Cu-In and Ag-In alloys are quite different from those of the liquid Au-In system, in which activities show considerably negative deviations in the whole concentration range, owing to the larger electronegativity factor in the gold alloys.