A multi-technique study of “barrier layer” nano-porosity in Zr oxides during corrosion and hydrogen pickup using (S)TEM, TKD, APT and NanoSIMS

Jing Hu, Thomas Aarholt, B. Setiadinata, K. Li, Alistair Garner, Sergio Lozano-Perez, Michael Moody, Philipp Frankel, Michael Preuss, C. Grovenor

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Abstract

We have used (S)TEM, TKD, NanoSIMS and APT to study nano-porosity in the oxide grown on deuterated Zr-1.0Nb and Zr-2.5Nb alloys. A detailed analysis of “barrier layer” nano-porosity by TEM and TKD has revealed that the oxide grain structure is much more disorganised and the nano-porosity network better developed in the rapidly oxidising post-transition alloy. Direct observations of the trapped deuterium (D) distributions from NanoSIMS analysis also shows much more penetration of the oxide layer post-transition. APT analysis shows that there is Fe and D segregation to some of the oxide grain boundaries with occasional evidence of porosity containing trapped D and H. We conclude that interconnected porosity would offer a dominant pathway for the transport of hydrogenic species to the metal substrate during the aqueous corrosion of zirconium alloys in service.

Original languageEnglish
Article number108109
Number of pages12
JournalCorrosion Science
Volume158
DOIs
Publication statusPublished - Sep 2019
Externally publishedYes

Keywords

  • Atom probe tomography
  • Corrosion
  • Fresnel imaging
  • Hydrogen pickup
  • Nano-porosity
  • NanoSIMS
  • Transmission Kikuchi diffraction
  • Zr alloys

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