Barrier oxide chemistry and hydrogen pick-up mechanisms in zirconium alloys

The chemistry of barrier oxide layers formed on zirconium alloys was investigated using atom probe tomography (APT). Grain boundary segregation of Fe and Ni was observed. The Zr(Fe, Cr)2 particles maintain a constant Zr:Fe:Cr ratio through the oxide until they reach an oxygen content of approximately 50 at%, when Fe depletion occurs. Enrichment of hydrogen along oxide crystallite boundaries was observed, which is interpreted as a sign of ingress...