A REVIEW OF THE KINETICS AND MECHANISMS OF OXIDATION AND HYDRIDING OF ZIRCONIUM, ZIRCALOY-2 AND Zr-22% Nb ALLOY

摘要

The widely scattered and often contradictory evidence on the kinetics and mechanisms of the oxidation and hydriding of zirconium and two of its technologically important alloys at temperatures below 400 C is reviewed.nFor reaction with oxygen, four distinct regions of the oxidation curves are defined. The control of the oxidation may differ in each of these regions, proceeding from an initial interface reaction through two stages of control by lattice diffusion of anions in the growing oxide film, to leakage path diffusion and finally to a complex equilibrium situation in the ' post-transition' region.nSome of the evidence indicates that the nature of the oxidation may not be the same in steam or water as in oxygen, and that wide generalisa¬tions may not be possible.