ジルコニア固体電解質電池法による溶融Cu-In系合金の活量測定

抄録

The activity of the liquid Cu-In system has been determined by the emf measurements of the following galvanic cell:
⊕Pt/Ni(s), NiO(s)/ZrO₂(+CaO)/Cu-In(l), In₂O₃(s)/Ir/Pt\ominus (for N_In=0.20−0.85 at 937-1270 K).
Deviations of the activities of indium and coppor from Raoult’s law are positive for the indium rich region and are negative for the copper rich side of the system. The present result agreed approximately with the data measured by Azakami and Yazawa.
The α functions of indium for the system show the curves against N_In, suggesting that the alloys can not be considered as the regular solution.
Heats of mixing are negative for copper rich alloys and slightly positive for indium rich alloys. The maximum and minimum values of the heats of mixing for the system are 0.40 kJ/mol at about N_In=0.76, −2.40 kJ/mol at about N_In=0.24, respectively.
The thermodynamic properties of liquid alloys composed of IB metals (Cu, Ag and Au) and indium have been discussed in terms of the alloy solution theory of Engel. Namely, the activities and the heats of mixing for liquid alloys seem to be consistently explained on the assumption that the filling of the d shell is incomplete for the IB metals as well as the transition metals, whereas it is complete for indium.
The activities and the heats of mixing of liquid Cu-In and Ag-In alloys are quite different from those of the liquid Au-In system, in which the activities show considerably negative deviations and the heats of mixing are exothermic, in the whole concentration range, owing to the larger differences of electronegativity factor in the gold alloys.