抄録
The activity coefficient of Si in Cu–Si alloy and Cu–Si–Fe alloys was determined using three principles at 1623 K. Cu–Si(–Fe) alloys at a low Si concentration were equilibrated with SiO2 in a graphite crucible under a controlled CO partial pressure. Cu–Si(–Fe) alloys at a medium Si concentration were equilibrated with SiC in a graphite crucible. And finally, Cu–Si(–Fe) alloys at a high Si concentration were equilibrated in a Si3N4 crucible under a controlled partial pressure of N2. The activity coefficients of the alloys were calculated based on the equilibrium Si concentration. The results show that the activity coefficient of Si in Cu–Si–Fe alloy decreases with an increase in the concentration of Fe. The results were evaluated in terms of the interaction parameters in molten Cu for Wagner’s formalism, and the interaction coefficient in the concentrated solution.The evaluated thermodynamic properties of Cu–Si–Fe alloy indicated that the addition of Fe to Cu–Si alloy is effective in decreasing the activity of Si in the alloy.
