Evaluation of isotope diffusion coefficient and surface exchange coefficient of ScSZ series oxide by oxygen isotope exchange method

In this work, the Isotope diffusion coefficient (D*) and surface exchange coefficient (k*) of Sc2O3 stabilized ZrO2 (ScSZ) series oxide, 6mol% Sc2O3-ZrO2 (6ScSZ), 10mol% Sc2O3-ZrO2 (10ScSZ) and 10mol% Sc2O3- 1mol% CeO2-ZrO2 (10Sc1CeSZ) were evaluated by using oxygen isotope exchange method. It was found that these ScSZ oxides showed a relatively higher D* value; 10Sc1CeSZ showed 1.1×10−7cm2s−1, 10ScSZ showed 9.3×10−8cm2s−1 and 6ScSZ showed 6.1×10−8cm2s−1 at 711°C, respectively. In addition, its activation energy was 1.0eV for 10Sc1CeSZ, 1.1eV for 10ScSZ and 1.0eV for 6ScSZ, respectively. The rapid change of D* due to the phase transition was also confirmed at around 600°C in the case of 10ScSZ. The surface exchange coefficient (k*) of these ScSZ oxides showed a relatively high value at lower temperature. 10Sc1CeSZ showed 1.3×10−8cms−1 at 498°C under lower vapor pressure of less than 20Pa.