Activities of phosphorus in copper-iron liquid alloys saturated with copper-iron solid solutions

(1)) Ferrous Metallurgy Research Group, Deptartment of Energy Science and Technology, Kyoto University, Kyoto / Japan; (2)) Steelmaking Research Department, JFE-Steel Corp., Fukuyama / Japan; (3)) Environmental Solution Center, JFE-Holdings, Tokyo / Japan; In order to determine the activities of phosphorus and iron in liquid {Cu-Fe-P} alloys, the two coexisting phases of liquid (Cu-Fe-P) alloys + <Cu-Fe-P> solid solutions were brought into equilibrium with a mixture of Al2O3 + AIPO(4) + FexAl2O4 at temperatures of 1416K and 1526K. The oxygen partial pressures were measured with the aid of a solid-oxide galvanic cell of the type: (+)MO / MO + MoO2 / ZrO2(MgO) / {Cu-Fe-P) + <Cu-Fe-P> + <Al2O3> + <AIPO(4)> + <FeAl2O4> / Fe(-) The equilibrium reactions underlying the experiments can be expressed by 2[P](Cu) + (5/2) (O-2) + <Al2O3> = 2 <AIPO(4)> and x[Fe]c + (1/2) (O-2) + <Al2O3> = <F%Al2O4> The Henrian activity coefficient referred to 1 wt pct solution in pure liquid copper could be well expressed by the formula log f(p)(o) = (4.46 +/- 0.40) - (8.67 +/- 0.59)/(T/K). The iron activities referred to pure solid iron could be formulated as log a(Fe) =- (0.37 +/- 0.12) + (500 +/- 200) /(T/K).