Diffusivity, activity and solubility of oxygen in liquid lead and lead–bismuth eutectic alloy by electrochemical methods

Abstract

The diffusivity of oxygen in liquid lead and lead–bismuth eutectic (LBE) alloy was measured by a potentiostatic method and is given by log ( D O Pb / cm 2 s - 1 ) = - 2.554 - 2384 / T ( ± 0.070 ) , 818–1061 K, and log ( D O LBE / cm 2 s - 1 ) = - 0.813 - 3612 / T ( ± 0.091 ) , 811–980 K. The activity of oxygen in lead and LBE was determined by coulometric titration experiments. Using the measured data, the standard free energy of dissolution of oxygen in liquid lead and LBE was derived and is given by G O ( Pb ) xs = - 121 349 + 16.906 T ( ± 560 ) J ( g atom O ) - 1 , 815 – 1090 K , G O ( LBE ) xs = - 127 398 + 27.938 T ( ± 717 ) J ( g atom O ) - 1 , 812 – 1012 K . Using the above data, the Gibbs energy of formation of PbO(s) and equilibrium oxygen pressures measured over the oxygen-saturated LBE alloy, the solubility of oxygen in liquid lead and LBE were derived. The solubility of oxygen in liquid lead and LBE are given by log( S/at.%O) = −5100/ T + 4.32 (±0.04), 815–1090 K and log( S/at.%O) = −4287/ T + 3.53 (±0.06), 812–1012 K respectively.