DETERMINATION OF THE OXYGEN SELF-DIFFUSION COEFFICIENTS IN Y2O3-CONTAINING TETRAGONAL ZIRCONIA POLYCRYSTALS BY RAMAN SPECTROMETRIC MONITORING OF THE O-16-O-18 EXCHANGE-REACTION

A new method of determining the oxygen self-diffusion coefficients (D) in oxides has been developed. The method is based on Raman spectrosco py combined with the O-16-O-18 exchange technique. By using the time d ependent O-18(2) concentration measured in a quasi in situ manner by R aman spectroscopy, the oxygen self-diffusion coefficients are calculat ed. The calculation takes into account the influence of the surface ex change reaction and the limited gas volume. The result obtained in 2.8 mol% Y2O3-containing tetragonal zirconia polycrystals is D = 1.55 (+0 .07/-0.07) x 10(-2) exp [(-120.0 +/- 0.4) (kJ/mol)/RT] cm2/sec. It was demonstrated that Raman spectroscopy is a useful tool for determining the oxygen self-diffusion coefficients in oxides.