Oxidation of Cobalt at High Temperatures and Self-Diffusion in Cobaltous Oxide

Abstract

The cobalt-cobaltous oxide-oxygen system has been for many years a subject of much interest owing to its model character in studies on kinetics and mechanism of metal oxidation,as well as on semiconducting and transport properties of transition metal oxides. In the present work an attempt has been made to determine precise values of parabolic rate constants of cobalt oxidation in the wide range of temperatures /950–1300°C/ and oxygen pressures /6.58 · 10−4–0.658 atm/. From these data self-diffusion coefficients of cobalt in cobaltous oxide /Co1-y0/ and activation energy and the pressure dependence of this process have been calculated. The total concentration of defects in cobaltous oxide as dependent on two parameters mentioned above have been also derived.