Identification of the Zirconia Phases by Means of Raman Spectroscopy for Specimens Prepared by FIB Lift-Out Technique

The zirconium–zirconia interface that developed during high-temperature corrosion of pure zirconium was investigated. Samples were oxidized at 600 °C in air at atmospheric pressure. The oxidized sample was then prepared by means of focused ion beam (FIB) lift-out technique and examined using Raman spectroscopy technique in three different oxide zones (external, internal, and close to the metal–oxide interface). Structural investigation was performed using line mode Raman analysis. Implementation of these techniques revealed complexity of the studied system and confirmed the presence of a thin tetragonal sub-layer located in the proximity of the metal. Recorded Raman band displacements of monoclinic and tetragonal phases were interpreted in terms of stoichiometry level and compressive stress in the oxide. The thin layer of tetragonal phase is most likely characterized by lower amount of oxygen than the external part of the oxide.