Corrosion protection of zirconium surface based on Heusler alloy

Abstract

Fe and Si films were tested as corrosion protection layers for Zr in nuclear industry applications. Surface chemistry of Zr in dependence on the preparation conditions and layout of the films was complexly investigated by various spectroscopic and microscopic techniques. Corrosion experiments were carried out in autoclave conditions with in-situ Electrochemical Impedance Spectroscopy. A clean Zr surface is characteristic with disposition to disorder and rough morphology demonstrated in facets, steps or terraces. Upon deposition of Fe and Si atoms in amounts in the order of single monolayers and subsequent annealing at 400°C, the original (1×1) Zr surface structure rearranges into (2√3×2√3)R30°. Corrosion experiments show that a thicker Si overlayer successfully suppresses oxygen uptake of the underlying Zr material by forming a diffusion barrier. The barrier effect of the films was also confirmed for hydrogen.