Synergistic effects of ultraviolet radiation and corrosion on Zr alloys

Abstract

Ultraviolet (UV) radiation and corrosion can be coupled in non-trivial ways and such coupling is of critical importance for the performance of materials in extreme environments. However, the confluence of these phenomena and their collective impact remains underexplored. This study bridges this knowledge gap by presenting a thorough investigation of Zr alloys exposed to corrosive high-temperature water under in-situ UV irradiation. We found that initial UV exposure significantly accelerates corrosion and induces distinct changes in the microstructure of ZrO2 oxides. Over time, we observed the formation of Fe3O4 particles on the ZrO2 surface due to photo-dissolution of zirconia and photo-deposition of iron oxide magnetite. The emergence of Fe3O4 particles could enhance the corrosion resistance of the Zr alloy substrate. Furthermore, our results indicate that UV irradiation modulates the density and distribution of nanopores within the oxide layer by influencing oxygen speciation and the dynamics of oxide growth. These insights advance our understanding of the complex interplay between UV irradiation and high-temperature water corrosion.