KINETICS OF OXIDATION OF ZIRCALOY-4 IN STEAM AT HIGH-TEMPERATURES

The kinetics of oxidation of Zircaloy-4 in steam were examined under isothermal conditions from 900° to 1500” C. Rate curves describing the growth of the reaction product layers, oxide- and oxygen-stabilized alpha, were obtained at 50°C intervals under carefully defined and documented experimental • conditions. The early stages of oxidation for temperatures above 1000°C were shown to be virtually ideally parabolic; below 1000°C, the growth of the oxide layer was nonparabolic. Statistical evaluations of the data in terms of the rate constants and their Arrhenius parameters established the high degree of self-consistency of these measurements. The features of the experimental apparatus and techniques that were necessary to insure accurate measurements are discussed. © 1979, The Electrochemical Society, Inc. All rights reserved.