Raman spectral characterization of existing phases in the ZrO2–Y2O3–Nb2O5 system

Tetragonal zirconia polycrystals (TZPs) were prepared with additions of 5.31 mol% Y2O3 plus up to 5 mol% Nb2O5 and their existing phases were investigated by Raman spectroscopy and X-ray diffraction. The present study reveals that Raman spectroscopy can identify the existing phases of cubic (c)-, tetragonal (t)-, monoclinic (m)-ZrO2, and Y–Nb ordered phase. The phase stability of t-ZrO2 may be governed by the competition between stable and transformable t-phase as a function of Nb2O5 content. Raman spectra of TZPs exhibit a broad and diffuse peak at around 770 cm−1 in contrast to the c-, t- and m-phases due to local ordering. The local environment of Nb5+ in this system is maintained throughout Nb2O5 concentrations (0