Raman Spectrometric Determination of the Oxygen Self-Diffusion Coefficients in Oxides

New methods of determining the oxygen self-diffusion coefficients (D*o) in oxides have been developed using Raman spectroscopy combined with the 16O–18O exchange technique. From the depth-profiles of the 18O concentration in the 16O–18O exchanged oxides, which was measured by Raman microscope with a spatial resolution of 5 μm, D*o was determined for 2.8 mol% Y2O3-containing tetragonal zirconia polycrystall (the depth-profile method). Thus-obtained results are expressed as D*O,D-P= 1.82(+0.41−0.40) × 10−1·exp{−(139.3 ± 0.2) [kJ/mol]/RT} [cm2/s] in the temperature range of 700–950°C. We also determined D*o for the same sample from the Raman spectrometric monitoring of the ambient gas during the 16O–18O exchange reaction (the gas-monitoring method). Thus-obtained results are expressed as D*O,G-M= 1.14(+0.05−0.04) × 10−2 exp{−(117.5 ± 0.4) [kJ/mol]/RT} [cm2/s] in the temperature range of 700–1165°C. The results obtained from the above two different methods virtually agree with each other, indicating that reliable D*o can be obtained by either of these two methods. We demonstrate that Raman spectroscopy is a useful tool for determining D*o in oxides.