Oxygen surface exchange was measured for Y0.2Ce0.8O2-x (YDC) and Y0.15Zr0.85O2-y (YSZ) over a wide range of oxygen partial pressures (7.3 × 10-21 to 0.17 bar) by isotope oxygen exchange (18O/16O) using secondary-ion mass spectrometry analysis at 973 K. Diffusion depth profiles of 18O in YDC and YSZ were analyzed by an appropriate fitting equation to calculate diffusion coefficient (D) and surface exchange coefficient (k). The diffusion coefficients (D) for YDC and YSZ are consistent with the reference data. The k values for both materials were similar (about k = 5-9 × 10-8 cm s-1) at the same temperatures. The k value increases with decreasing oxygen partial pressure for both YDC and YSZ. A relationship between the k value and the concentrations of electron and oxygen vacancy is discussed.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Materials Science(all)
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering