On Raman spectroscopy of zirconium oxide films

Using Raman spectroscopy, we studied samples of pure tetragonal and monoclinic zirconia powders, and oxide film developed at 400 degrees C in steam (autoclave) on Zircaloy-4 with various tin contents. We analyze the absolute intensities of the bands and background, as well as the position of the bands. All these parameters bring some surprising evolution with tin content and oxidation time, relatively to the powders. We have shown that the films are mainly monoclinic, but that the second phase is not similar to the tetragonal phase observed in powders. It is probably a distorted tetragonal phase. The oxide films are not homogeneous through their thickness, being better crystallized near the surface. This prevents to compute directly any relevant tetragonal fraction from the band intensities. The presence of tin induces a high background, probably related to the existence of numerous oxygen vacancies. The absorption coefficient of the films at 514 nm is about 0.4 mu m(-1). (C) 1997 Elsevier Science B.V.