Electrochemical study on determination of diffusivity, activity and solubility of oxygen in liquid bismuth

Abstract

Diffusivity of oxygen in liquid bismuth was measured by potentiostatic method and is given by lg(D-o(Bi)/cm(2) . s(-1))(+/- 0.042) = -3.706 - 1377/(T K-1) (804 < T/K < 1090). Activity of oxygen in bismuth was determined by coulometric titrations and using the measured data standard free energy of dissolution of oxygen in liquid bismuth was derived for the reaction: 1/2O(2) (g) = [O](Bi) (at.%) and is given by Delta G(O(Bi))(o)/(J . g-atom O-1)(+/- 720) = -108784 + 20.356T K-1 (753 < T/K < 1020). Using the above data and Gibbs free energy of formation of Bi2O3 (s), solubility of oxygen in liquid bismuth was derived as a function of temperature and is given by the following expressions: lg(S/at%O)(+/- 0.05) = -4476/T K-1 +4.05 (753 < T/K < 988); lg(S/at.%O)(+/-0.04) -3786/T K-1 + 3.36 (988 < T/K < 1020). The present data on solubility of oxygen in liquid bismuth is compared with the literature data. (C) 2005