Abstract
E.M.F. of a galvanic cell with the solid electrolyte (ZrO2+CaO) was measured to determine the activities of nickel in the temperature range of 900∼1100°C for eight Cu-Ni alloys, and the activities of molybdenum in the temperature range of 950∼1100°C for eight Ni-Mo alloys, and thermodynamic functions were derived from the determined activities. The cells were as follows;
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In the Cu-Ni alloys, activities showed positive deviations from Raoult’s law, and enthalpies of mixing showed positive values and excess entropies of mixing showed small negative values. These results were in good agreement with other reliable data.
In the Ni-Mo alloys, activities of molybdenum showed large positive deviations from Raoult’s law, and those of nickel small negative deviations in the nickel rich solid solution range. The alloy system is characterized by large positive enthalpies and entropies of mixing. They are probably due to the elastic strain energy derived from the large size difference between nickel and molybdenum.
