The Oxidation of a Monophase Co-8.03 Wt% Cu Alloy at 700 to 1000 C

The oxidation of a monophase cobalt-copper alloy at high temperature has been studied to examine the effect of the copper addition to cobalt on the oxidation kinetics as well as on the scale morphology and composition. The rate law remains parabolic as for pure cobalt but the rate constant is higher at all temperatures. This result is interpreted as being due mainly to the doping of CoO by monovalent copper ions by means of a detailed calculation of the rate constant for the alloy making use of the experimental profile of the copper concentration in the scale and of a suitable model for the defect structure of cobalt oxide.