Diffusivity and solubility of oxygen in solid palladium

Abstract

The solid solubility c O of oxygen in palladium in equilibrium with gaseous oxygen has been determined from absorption-desorption experiments for temperatures T of 1123 and 1173 K and oxygen partial pressures po 2 between 2.7 × 103 and 4.0 × 104 Pa. The relationship between c O, po2 and T is given by c O = a\√po2 (- Δ Hs/RT), where R = 8.314 JK-1 mol-1 is the universal gas constant, ΔH s = -13.55 kJ/mol denotes the heat of solution of oxygen in palladium and the constant a amounts to $$ 4.26 × 10- 5 at.%/√Pa or 6.41 × 10-8} wt%/√Pa. The diffusion coefficient D O of oxygen in solid palladium has been determined by incomplete isothermal internal oxidation of Pd-Fe alloys using the data on the oxygen solubility in palladium. The temperature dependence of D O obeys the Arrhenius equation D O = D 0 exp(-E d/RT) with pre-exponential factor D 0 = 2.33 × 10-7 m2/s and activation energy of diffusion of oxygen in palladium, E d = 102.76 kJ/mol © 2008 Springer Science+Business Media, LLC.