Abstract
The activities of Zn in liquid Cu-Zn-X (X=Al, Ni) ternary alloys have been measured by the use of isopiestic method at temperatures 1423 K and 1373 K and in the composition range, NZn<0.09 and NX≤0.08. From the activity data the first and second order interaction parameters between Zn and X in molten Cu have been determined. The activity of Zn in Cu-Zn binary liquid alloys is increased by the addition of a small amount of Al and decreased by Ni. The activity coefficients of Zn in Cu-Zn-X ternary liquid alloys are well expressed by a quadratic relation,
lnγZn=lnγZn°+εZnZnNZn+εZnXNX+ρZnZnNZn2+ρZnXNX2+ρZnZnXNZnNX, in the composition range, NZn+NX≤0.10.
It has been demonstrated that the quadratic formalism proposed by Darken is valid for Cu-Zn-Al ternary liquid alloys in the composition range, NZn≤0.08 and NAl≤0.06.
