TY  - JOUR
AU  - Grünwald, Nikolas
AU  - Sohn, Yoo Jung
AU  - Yin, Xiaoyan
AU  - Menzler, Norbert H.
AU  - Guillon, Olivier
AU  - Vaßen, Robert
TI  - Microstructure and Phase Evolution of Atmospheric Plasma Sprayed Mn-Co-Fe Oxide Protection Layers for Solid Oxide Fuel Cells
JO  - Journal of the European Ceramic Society
VL  - 39
SN  - 0955-2219
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - FZJ-2018-05102
SP  - 449-460
PY  - 2019
AB  - Dense protective layers are needed to reduce chromium-related degradation in SOFC stacks. In particular, atmospheric plasma sprayed (APS) Mn1.0Co1.9Fe0.1O4 (MCF) coatings demonstrated low degradation rates in stack tests. We show that short-term annealing in air induces crack healing within these coatings. Parallel to this effect, a phase transformation is observed originating from oxidation that proceeds by solid state-diffusion. The present contribution reveals the basic mechanisms of the microstructural and phase changes of coatings in long-term annealing tests of up to 10,000 h at 700 °C. The layer develops differently at the air-facing surface and in the bulk. Due to cation deficiency, oxidation is dominated by cation outward diffusion, leading to a Co-enriched surface layer. The bulk displays a fine distribution of the initial (rock salt) and the final (spinel) phases. Understanding the mechanisms leading to these irreversible changes enables predictions to be made concerning durable protectivecoatings in SOFCs.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000450379400040
DO  - DOI:10.1016/j.jeurceramsoc.2018.08.027
UR  - https://juser.fz-juelich.de/record/851466
ER  -