The relationship between the amount of oxidation and activation energy on the steam oxidation reaction of Zircaloy-4 cladding

The oxidation rate of the specimen decreased with increasing heating rate. The activation energy of oxidation was evaluated based on a non-isothermal kinetics theory. It was found that the activation energy of oxidation depends on the specimen weight gain. The activation energies showed constant values of ∼300 and ∼180 kJ/mol in the oxidation range between 30 and 120 g/m2 and above 120 g/m2, respectively. A master curve which expresses the amount of steam oxidation of Zircaloy-4 cladding was formulated based on the activation energies obtained.