Diffusion of oxygen in the scales of Fe–Cr alloy interconnects and oxide coating layer for solid oxide fuel cells

Autor: Yueping Xiong, Teruhisa Horita, Harumi Yokokawa, Yoshio Matsuzaki, Manuel E. Brito, Katsuhiko Yamaji, Toshihiro Uehara, Yoshitaka Baba, Satoshi Yamashita, Harukuni Kameda, Nobutaka Yasuda, Haruo Kishimoto, Kei Ogasawara
Rok vydání: 2008
Předmět:
Zdroj: Solid State Ionics. 179:2216-2221
ISSN: 0167-2738
Popis: Oxygen diffusivity was examined in the oxide scales formed on Fe–Cr alloy surface and Mn–Co spinel coating layer. The stable isotope oxygen ( 18 O 2 ) was adopted to visualize the diffusion profiles of oxygen in the oxide scales and coating layer. A relatively fast diffusivity of 18 O was observed (diffusion coefficients were 10 − 12 cm 2 s − 1 orders of magnitude at 1073 K) in the oxide scale. MnCo 2 O 4 spinel coating was examined on the Fe–Cr alloy surface to clarify the 18 O diffusion in the coating oxide layer. Two drops of 18 O diffusion profiles were observed in the MnCo 2 O 4 spinel coating layer; first one was at surface region and second was MnCo 2 O 4 spinel coating/alloy interface. Relatively fast 18 O diffusion coefficients were observed on the Mn–Co spinel surface (the diffusivities of 18 O were 10 − 13 –10 − 12 cm 2 s − 1 at 1073 K). A significant fast diffusivity of 18 O was observed in the middle of the MnCo 2 O 4 spinel coating. The second drop of 18 O concentration can be related to the existence of Cr around the MnCo 2 O 4 spinel coating/alloy interfaces. The growth rate of oxide scale was controlled by the existence of Cr around the oxide scale/alloy or oxide coating/alloy interfaces.
Databáze: OpenAIRE
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