%0 Journal Article
%A Grünwald, Nikolas
%A Sohn, Yoo Jung
%A Yin, Xiaoyan
%A Menzler, Norbert H.
%A Guillon, Olivier
%A Vaßen, Robert
%T Microstructure and Phase Evolution of Atmospheric Plasma Sprayed Mn-Co-Fe Oxide Protection Layers for Solid Oxide Fuel Cells
%J Journal of the European Ceramic Society
%V 39
%@ 0955-2219
%C Amsterdam [u.a.]
%I Elsevier Science
%M FZJ-2018-05102
%P 449-460
%D 2019
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000450379400040
%R 10.1016/j.jeurceramsoc.2018.08.027
%U https://juser.fz-juelich.de/record/851466