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Self-diffusion in high-purity a-Al2O3: Comparison of Ti-doped, Mg-doped and undoped single crystals

Fielitz, Peter and Ganschow, Steffen and Borchardt, Günter and Kelm, Klemens (2020) Self-diffusion in high-purity a-Al2O3: Comparison of Ti-doped, Mg-doped and undoped single crystals. Journal of the European Ceramic Society, 41, pp. 663-668. Elsevier. doi: 10.1016/j.jeurceramsoc.2020.07.064. ISSN 0955-2219.

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Official URL: https://www.sciencedirect.com/journal/journal-of-the-european-ceramic-society/vol/41/issue/1

Abstract

Oxygen diffusivity in α-alumina is characterised by a scatter band of about one decade and a half in an Arrhenius diagram. In order to control decisive material parameters the present study is based on high-purity single crystals which were deliberately doped with aliovalent elements (Mg or Ti) and simultaneously annealed in an 18O2 atmosphere (200 mbar at 1650 °C). In such a crucial experiment the diffusivities in undoped and acceptor or donor doped alumina are identical within a factor of about 2. Contradictory findings in the past on the impact of Mg and Ti on the oxygen diffusion can be rationalised due to published similar calculated energies for the most probable dopant incorporation reactions. Al self-diffusion is much more rapid than oxygen diffusion in undoped and Ti-doped α-alumina. In this work we show for the first time that Mg doping drastically reduces the Al diffusivity in α-alumina.

Item URL in elib:https://elib.dlr.de/136973/
Document Type:Article
Title:Self-diffusion in high-purity a-Al2O3: Comparison of Ti-doped, Mg-doped and undoped single crystals
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Fielitz, PeterTechnische Universität Clausthal, Institut für Metallurgie, Robert-Koch-Str. 42, D-38678 Clausthal-ZellerfeldUNSPECIFIED
Ganschow, SteffenLeibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, D-12489 BerlinUNSPECIFIED
Borchardt, GünterTechnische Universität Clausthal, Institut für Metallurgie, Robert-Koch-Str. 42, D-38678 Clausthal-ZellerfeldUNSPECIFIED
Kelm, KlemensKlemens.Kelm (at) dlr.deUNSPECIFIED
Date:2 August 2020
Journal or Publication Title:Journal of the European Ceramic Society
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:41
DOI :10.1016/j.jeurceramsoc.2020.07.064
Page Range:pp. 663-668
Publisher:Elsevier
ISSN:0955-2219
Status:Published
Keywords:Alumina Ti-doped Mg-doped Tracer diffusion SIMS
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Transportation
DLR - Research area:Raumfahrt
DLR - Program:R RP - Space Transportation
DLR - Research theme (Project):R - Wiederverwendbare Raumfahrtsysteme (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > Microanalysis
Deposited By: Kelm, Dr. Klemens
Deposited On:03 Nov 2020 10:17
Last Modified:03 Nov 2020 10:17

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