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@PHDTHESIS{Keuter:202881,
author = {Keuter, Thomas},
title = {{I}nnenbeschichtung poröser {K}örper mittels
{A}tomlagenabscheidung zur {R}edoxstabilisierung
anodengestützter {F}estoxidbrennstoffzellen},
volume = {273},
school = {Universität Bochum},
type = {Dr.},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2015-05029},
isbn = {978-3-95806-069-2},
series = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
Umwelt / Energy $\&$ Environment},
pages = {XII, 133 S.},
year = {2015},
note = {Universität Bochum, Diss., 2015},
abstract = {Fuel cells convert directly the chemical energy of fuels
into electrical energy with a high efficiency and are
flexible in use due to their modular design. Anode-supported
Solid Oxide Fuel Cells (SOFCs) consist of a nickel/8YSZ
substrate (8YSZ ˆ= with 8 $mol-\%$ yttria stabilized
zirconia), a nickel/8YSZ anode, an 8YSZ electrolyte, and a
cathode. In case of reoxidation of the nickel in the
substrate, the substrate expands in lateral direction and
creates tensile stresses and cracks in the electrolyte,
resulting in a decrease of the cell performance or a
complete cell failure. The aim of this work is the
stabilization of anode-supported SOFCs with respect to
reoxidation by coating the inner surface of the porous
substrate, using the process of atomic layer deposition
(ALD). The deposited layer protects the nickel in the
substrate against oxidation and prevents in this way a crack
formation in the electrolyte and a cell failure. More
generally, the inner surface coating of porous media using
ALD is investigated experimentally and described
theoretically by a model. Atomic layer deposition of
zirconia using the precursors TEMAZ and O$_{2}$ was
developed in the in-house ALD machine, because this process
is not described in literature. In order to model atomic
layer deposition, Knudsen diffusion and second-order surface
reaction kinetics of the precursors were combined and the
thickness of the deposited layer within the porous medium
was predicted. The inner surface coating of Ni/8YSZ
substrates was proven by a conformal coating of the grains
and the ALD model was verified. The zirconia layer protected
the coated parts of the substrate for at least 17 redox
cycles. It was not possible to coat the entire inner surface
of the substrate and consequently, reoxidation of the
substrate led to cracks in the electrolyte. The zirconia
layer did not influence the electrochemical performance of
the SOFC leading to the conclusion that a complete coating
of the substrate can solve the problem of reoxidation.
Additionally, the combination of a thin electrolyte and a
low operating temperature is promising, too.},
cin = {IEK-1},
cid = {I:(DE-Juel1)IEK-1-20101013},
pnm = {899 - ohne Topic (POF3-899) / HITEC - Helmholtz
Interdisciplinary Doctoral Training in Energy and Climate
Research (HITEC) (HITEC-20170406)},
pid = {G:(DE-HGF)POF3-899 / G:(DE-Juel1)HITEC-20170406},
typ = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
url = {https://juser.fz-juelich.de/record/202881},
}