Abstract
Using an emf technique in concentration cells with solid electrolytes in the scheme Pt, Ni+NiO/ZrO2+CaO/O in liquid Cu/Cr cermet,Pt, oxygen activity in liquid copper at temperatures of 1100° and 1200°C was determined. The oxygen content of liquid copper was varied by addition of solid CU2O. The results obtained show that at concentrations of oxygen up to 0·5 at.-%, Henry's law is valid. The results on the limiting activity coefficients of oxygen at 1100° and 1200°C and on the standard free energy of oxygen dissolution in liquid copper show good agreement with published data.