Activity of Oxygen in Liquid Cu–Tl Alloys

Abstract

In order to determine the activity coefficients of oxygen, γ_O, in liquid Cu–Tl alloys at 1373 K as a function of alloy composition, the modified coulometric titrations described previously have been performed by using an electrochemical cell: O in liquid Cu–Tl alloys/ZrO₂(+CaO)/Air, Pt. The activity coefficients of oxygen in liquid copper and thallium are considerably lowered by a little addition of thallium and copper respectively so that a deep upwardly concave curve of lnγ_O vs alloy composition is suggested over the entire composition range of Cu–Tl alloys. The interaction parameter of thallium on oxygen is evaluated to be −7.5 at 1373 K . The present results have been compared with the calculated values based on solution models.