Multi-scale characterisation of oxide on zirconium alloys

Abstract Multi-scale characterisation using TEM, EELS and 3D FIB reconstruction was carried out on both pre-transition and post-transition oxides grown in high-temperature water. 3-D characterisation of cracks using high resolution FIB sequential sectioning gave a quantitative measure of crack density over time. There is no sudden burst of cracking occurring at the kinetic transition. On the nanometre scale, Fresnel contrast was used to reveal porosity of 1 – 3 nm in size in the oxide, which develops during growth from isolated pores to a connected network. Quantification of oxygen concentration using STEM-EELS has identified a suboxide, ZrO, layer tens of nanometres thick at the metal – oxide interface.