Abstract
The same apparatus was used as in the previous study. In the experimental operation, we took special care to avoid the experimental error in the e.m.f. data introduced by dissolution of graphite in nickel-rich alloy. From the results obtained by experiments at the temperatures 1470° and 1510°, it has been shown that the relationship between the e.m.f. and the mole fraction of silicon at 1470° is represented by a curve with curvatures which lies below the approximately smooth curve for 1510°. Moreover, it is found that the activity curves in molten Ni-Si alloys show large negative deviation from Raoult’s law.