Journal article
Accelerated ceria–zirconia solubilization by cationic diffusion inversion at low oxygen activity
Department of Energy Conversion and Storage, Technical University of Denmark1
Ceramic Engineering & Science, Department of Energy Conversion and Storage, Technical University of Denmark2
Imaging and Structural Analysis, Department of Energy Conversion and Storage, Technical University of Denmark3
Universidade Federal do ABC4
Fast elemental diffusion at the Gd-doped ceria/Y-stabilized zirconia interface occurs under reducing conditions at low oxygen activity (pO2 < 10−12 atm) and high temperature (1400 °C). This effect leads to formation of thick ceria–zirconia solid solution reaction layers in the micro-range vs. thin layers of few tens of nanometers under oxidative conditions (i.e. in synthetic air at pO2 = 0.21 atm).
The fast dissolution occurs by an inversion of the dominating limiting mechanism from the expected Zr4+ diffusion into the CGO lattice at high pO2 to an unexpected Ce3+ diffusion into the YSZ component under reducing conditions. The diffusion coefficient of 8-fold coordinated Ce3+ in YSZ at 1400 °C and pO2 = 10−13 atm is estimated to be around 10−11 cm2 s−1.
This value is around 3 orders of magnitude higher than Zr4+ interdiffusion in CGO under oxidative conditions and about 8 orders of magnitude higher than Ce4+ self-diffusion in CGO in air at the same temperature.
Language: | English |
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Year: | 2016 |
Pages: | 16871-16878 |
ISSN: | 20507496 and 20507488 |
Types: | Journal article |
DOI: | 10.1039/C6TA06308J |
ORCIDs: | Esposito, Vincenzo , Marani, Debora , Teocoli, Francesca , Thydén, Karl Tor Sune and 0000-0003-0708-2021 |