AN XPS STUDY OF THE KINETICS OF DISSOLUTION OF ZRO2 IN ALPHA-ZR

The dissolution of a 15 Å thick oxide layer into polycrystalline Zr at temperatures between 440 and 600 K and under non‐oxidizing conditions has been studied by XPS. The thickness of the oxide layer as a function of the annealing time shows a parabolic dependence. It is then concluded that the rate of dissolution is controlled by diffusion into the Zr substrate of oxygen atoms, which generate at the interface by decomposition of the oxide. In addition, the effective oxygen diffusion coefficient in the 440–600 K temperature range has been determined as D = 4.42 × 10−6 exp(−99.7/RT) cm2 s−1, with the activation energy in kJ mol−1. Copyright © 1990 John Wiley & Sons Ltd.