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Phase Evaluation of YSZ upon Doping with Ta5+, Ti4+ and Ca2+ with Combined Raman and XRD Analysis
A. Bhattacharya1, T. Wermelinger2, V. Shklover1
1 Laboratory of Crystallography, Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
2 Institute of Nanometallurgy, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
received August 20, 2012, received in revised form November 1, 2012, accepted November 7, 2012
Vol. 3, No. 4, Pages 211-214 DOI: 10.4416/JCST2012-00028
Abstract
To improve the phase stability of 7YSZ (7 wt%-Y2O3-doped ZrO2), it has been doped with larger (Ca2+) and smaller (Ti4+ or Ta5+) ions. Complementary Raman and XRD studies of these stabilized systems have been performed. The tetragonal symmetry of the Ta5+-ion-doped YSZ sample and the Ti4+-doped YSZ sample, and the cubic symmetry of Ca2+-doped YSZ have been confirmed both by means of XRD and Raman analyses. Raman scattering measurements show shifts of characteristic peaks when the YSZ is doped with Ta5+, Ti4+ and Ca2+ cations. The peak shift increased with increasing dopant concentration in the ZrO2 lattice. The Ta-doped YSZ sample heat-treated below 1500 °C contained some YTaO4 phase, which was confirmed by means of XRD as well as by Raman spectroscopy. The effect of Ca2+ ion doping on the Raman peak shift was much higher than that of Y3+ ion doping. In this work it has been highlighted that Raman spectroscopy is a useful tool complementing XRD, for qualitative comparison of the doping effect on the lattice parameters of ZrO2.
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Keywords
TBC, YSZ, Raman spectroscopy, XRD, ZrO2
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