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Ferritic Cathodes Degradation by Potassium/Chromium Poisoning and Air Humidification
Author(s) -
Arregui A.,
RodriguezMartinez L. M.,
Modena S.,
Bertoldi M.,
Sglavo V. M.
Publication year - 2013
Publication title -
fuel cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.485
H-Index - 69
eISSN - 1615-6854
pISSN - 1615-6846
DOI - 10.1002/fuce.201300032
Subject(s) - cathode , materials science , chromium , degradation (telecommunications) , sintering , chemical engineering , delamination (geology) , diffusion , composite material , deposition (geology) , metallurgy , chemistry , electrical engineering , paleontology , physics , subduction , sediment , biology , tectonics , engineering , thermodynamics
Degradation mechanisms inherent to ferritic LSF‐SDC and LSCF‐GDC cathodes are studied by post‐mortem analysis of cells which suffered the most significant performance deterioration in a set of 18 500 h tests carried out under a specific experimental design. Three cathode processing parameters (composition, thickness, and sintering temperature) were combined with five operation conditions (chromium presence, current density, operating temperature, air flow, and humidification) through this design of experiments based in a L 18 Taguchi matrix. In the case of cells exposed to chromium vapors from Crofer 22 APU pieces, those cells which exhibited K 2 Cr 2 O 7 deposition in the cathode/GDC barrier interface underwent the most aggressive ASR degradation. Similar deposits were also observed on the surface of LSC current collectors. Two cells exposed to highly humidified air (20%) exhibited cathode delamination and GDC barrier deterioration by crack propagation though no foreign elements diffusion to the interface could be detected.