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@INPROCEEDINGS{Korte:1021705,
author = {Korte, Carsten and Franz, B.},
title = {{E}ffect of ({E}xternal) {E}lectric {F}ields on {T}he
{H}eterogeneous {S}olid {S}tate {R}eaction between {A}l2{O}3
and {Y}2{O}3 {F}orming {M}ultiple {P}roduct {L}ayers},
reportid = {FZJ-2024-00951},
year = {2023},
abstract = {Ceramics materials are used in many technologically
important applications, e.g. electronics, sensors, energy
conversion and storage. Solid state reactions as degradation
process play an important role at elevated temperatures,
especially in the case of short diffusion length
(miniaturisation) or if an extended lifetime is required.
This includes redox reactions and reactions only due to the
transport of ions, resulting in the (heterogeneous)
formation of product phases. Under working conditions,
devices are not only subjected to elevated temperatures but
also to electric fields, acting as a second driving force on
the mobile charge carriers in addition to chemical potential
gradients. Beyond, the importance for degradation processes,
the influence of electric fields on solid state reactions
gains also more importance for the preparation of ceramic
materials. In the last years the field-assisted (flash)
sintering (FAST) and the spark plasma sintering (SPS)
techniques were developed to a mature state.In this
experimental study the influence of an electric field on the
kinetics and morphological evolution on the heterogeneous
solid state reaction between Al2O3 and Y2O3 is highlighted.
The reaction couples were prepared in thin film technique by
pulsed laser deposition (PLD). Depending on the reaction
temperature, up to three product layers (garnet: YAG,
perovskite: YAP and a monoclinic phase: YAM) can be formed.
The kinetic parameters for the only thermally activated
reactions were determined. [1] In the presence of an
electric field, linear transport theory predicts a thickness
independent growth rate (time independent linear growth law)
for the product layers, only depending on the ionic current
and on the difference of the cationic transference numbers
in the product phases. This is different to the an only
thermally activated reaction, were the growth rate depends
on the Nernst-Planck coupled conductivities and the
reciprocal layer thickness (parabolic growth law).It is
shown for this solid state reaction that an electric field
will change the thickness ratio of the formed product phase
compared to the only thermally activated reaction. The
formation of the perovskite phase (YAP) is selectively
enhanced when connecting the Y2O3 layer to the cathode side.
[2] This may result from the different growth kinetics of
the product phases with and without an electric field. The
role of grain boundaries as fast diffusion paths is
enhanced, resulting in a product layer morphology different
to the non-field-driven reaction.[1] C. Korte and B. Franz,
Solid State Ionics 368, 115699 (2021)[2] B. Franz and C.
Korte, Solid State Ionics 383, 115978 (2022)},
month = {May},
date = {2023-05-29},
organization = {E-MRS 2023 Spring Meeting, Strasbourg
(France), 29 May 2023 - 2 Jun 2023},
cin = {IEK-14},
cid = {I:(DE-Juel1)IEK-14-20191129},
pnm = {1231 - Electrochemistry for Hydrogen (POF4-123)},
pid = {G:(DE-HGF)POF4-1231},
typ = {PUB:(DE-HGF)1},
url = {https://juser.fz-juelich.de/record/1021705},
}