Vibrational and electronic spectroscopic properties of zirconia powders

Ten zirconia powders have been characterized by XRD, FT-IR/FT-FIR and Raman skeletal spectroscopies and DR-UV electronic spectroscopy. The vibrational features of a yttria-stabilized cubic zirconia and of tetragonal, monoclinic and tetragonal + monoclinic pure zirconia mixtures have been discussed. Assignments for the vibrational features of cubic and tetragonal samples are proposed. The origin of very broad vibrational peaks in tetragonal zirconia is briefly addressed. The vibrational spectra provide evidence for the presence of trigonal oxide ions in the monoclinic phase only. The UV spectra show that monoclinic zirconia (where the coordination of zirconium is sevenfold) absorbs at lower energy than the cubic and tetragonal phases (where the coordination of zirconium is eightfold). However, it absorbs at higher energy than the perovskite SrZrO3 where Zr adopts octahedral coordination. The origin of the shifts of the corresponding absorption edges is discussed