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Chemical expansion of CeO₂₋δ and Ce₀.₈Zr₀.₂O₂₋δ thin films determined by laser Doppler vibrometry at high temperatures and different oxygen partial pressures

Title data

Kohlmann, Dhyan ; Wulfmeier, Hendrik ; Schewe, Marvin ; Kogut, Iurii ; Steiner, Carsten ; Moos, Ralf ; Rembe, Christian ; Fritze, Holger:
Chemical expansion of CeO₂₋δ and Ce₀.₈Zr₀.₂O₂₋δ thin films determined by laser Doppler vibrometry at high temperatures and different oxygen partial pressures.
In: Journal of Materials Science. Vol. 58 (2023) . - pp. 1481-1504.
ISSN 1573-4803

Official URL: Volltext

Project information

Project title:
Project's official title
Project's id
In-situ-Verfahren zur Bestimmung hoher Sauerstoffdefizite in Cer-Zirkon-Mischoxiden für den Einsatz in der Abgasnachbehandlung
MO 1060/29-1

Project financing: Deutsche Forschungsgemeinschaft

Abstract in another language

The chemical expansion of ceria (CeO2−δ) and ceria-zirconia (Ce0.8Zr0.2O2−δ, CZO80) thin films is investigated by high-temperature laser Doppler vibrometry (LDV) at temperatures from 600 to 950 °C. The films are deposited on single-crystalline 8 mol-% yttria-stabilized zirconia substrates, which act as pumping cells to adjust oxygen non-stoichiometry in the thin films. Oxygen deficiency causes film expansion, leading to mechanical strain that bends the sample. The total displacement, i.e., the sum of bending and film-thickness change, is determined contact-less by LDV. A differential laser Doppler vibrometer (D-LDV) is realized to enable measurements on a very long time scale, which is necessary due to the long equilibrium times of the ceramic films. These displacements are compared to those acquired with a commercial single-point laser Doppler vibrometer (SP-LDV) for motions above 1 Hz. Here, both devices yield similar results. CZO80 films are found to bend a substrate much more than ceria films under similar experimental conditions. A model describing the displacement of the sample is derived from the Stoney model and applied to calculate deflections using literature data. The displacements at the center of the CZO80 sample measured with the SP-LDV increase from 0.18 nm at 10 Hz and 600 °C to 32.7 nm at 0.1 Hz and 800 °C. For ceria, the displacements range from 1.6 nm (10 Hz, 800 °C) to 79.4 nm (0.1 Hz, 900 °C). The D-LDV enables the detection of quasi-static displacements at very low frequencies. The ceria sample exhibits 218 nm at 0.001 Hz and 800 °C.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties > Faculty of Engineering Science
Faculties > Faculty of Engineering Science > Chair Functional Materials > Chair Functional Materials - Univ.-Prof. Dr.-Ing. Ralf Moos
Profile Fields > Advanced Fields > Advanced Materials
Research Institutions > Research Centres > Bayreuth Center for Material Science and Engineering - BayMAT
Result of work at the UBT: Yes
DDC Subjects: 600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited: 06 Feb 2023 09:01
Last Modified: 06 Feb 2023 09:01