WITHDRAWN: Precession electron diffraction study on the microtexture of the zirconium oxide film in aqueous solutions

Abstract

The oxide film formed on zirconium alloy (Zr-0.45 Sn-0.38 Nb-0.30 Fe-0.05 Cu-0.015 Si-0.13 O, wt. %) respectively corroded for 300 days in 360 °C/18.6 MPa pure water and lithiated water was characterized using precession electron diffraction (PED). The results revealed that the grain morphology (columnar and equiaxed) and the grain crystallography orientation (angular deviation of {112¯}m-ZrO2 from the oxide growth direction) gradually changed periodically with the distance of metal/oxide (O/M) interface. In lithiated water sample, the proportion of oxide grains deviated from the {112¯}m-ZrO2 texture by 50-60° is higher than that in pure water, resulting in an early corrosion transition. This is attributed to that Li+ ions were unfavorable for the formation of well-oriented and coarse columnar grains. In the pure water, a small amount of hexagonal ZrO (h-ZrO) suboxide was found at the O/M interface where just go trough a high-rate corrosion transition, while in the lithiated water, a continuous h-ZrO suboxide layer was formed at the O/M interface where experiences a low-rate corrosion just before transition. This suggests that the present of suboxide layer greatly correlates to the instantaneous oxidation rate. Electron energy loss spectroscopy (EELS) further found that the presence of h-ZrO affected the oxygen level in the nearby substrate metal.