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Oxidation behavior of pack-cemented Si–B oxidation protection coatings for Mo–Si–B alloys at 1300 °C

Lange, Annika and Heilmaier, Martin and Sossamann, Travis A. and Perepezko, John H. (2015) Oxidation behavior of pack-cemented Si–B oxidation protection coatings for Mo–Si–B alloys at 1300 °C. Surface and Coatings Technology, 266, pp. 57-63. Elsevier. ISBN ISSN: 0257-8972 ISSN 0257-8972

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Official URL: http://ac.els-cdn.com/S0257897215001383/1-s2.0-S0257897215001383-main.pdf?_tid=3a6f5742-d38a-11e4-935a-00000aab0f02&acdnat=1427355316_f3c7e0c351dc69be6da4ee62bb3bf1e6

Abstract

To enhance the resistance to oxidation and prolong the lifetime, oxidation protection coatings were applied on Mo–9Si–8B (in at.%) alloy substrates by Si–B co-pack cementation. Subsequently, the samples were conditioned at 1450 °C for 8 h in air to develop an outer 10 μmthick aluminoborosilicate scale. A multilayered microstructure ofMoSi2,Mo5Si3, andMo5SiB2/MoB of about 80 μmthick was observed underneath the scale. During cyclic testing between room temperature and 1300 °C the samples exhibited a very low mass change of only up to +/−0.2 mg/cm2 within 500 h at high temperature. During oxidation the MoSi2 phase layer was partially consumed by silica and Mo5Si3 formation. No high material regression due to MoO3-evaporation took place during testing. However, a lowmass loss during the first 100 h of testingwas observed, presumably due to stress cracking caused by thermalmismatch of coating and substrate accompanied by subsequent healing. The stresses were reduced by the growth texture in the [001] direction of the Mo5Si3-phase. In comparison to the uncoated substrate material, the mass change was decreased by 99.8%. This points to a significantly prolonged lifetime and shows the huge potential of coated Mo–9Si–8B alloys for application at very high temperatures and under thermal cycling loads.

Item URL in elib:https://elib.dlr.de/95756/
Document Type:Article
Title:Oxidation behavior of pack-cemented Si–B oxidation protection coatings for Mo–Si–B alloys at 1300 °C
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Lange, Annikaannika.lange (at) dlr.deUNSPECIFIED
Heilmaier, MartinKITUNSPECIFIED
Sossamann, Travis A.University of Wisconsin, USAUNSPECIFIED
Perepezko, John H.University of Wisconsin, USAUNSPECIFIED
Date:17 February 2015
Journal or Publication Title:Surface and Coatings Technology
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:266
Page Range:pp. 57-63
Publisher:Elsevier
ISSN:0257-8972
ISBN:ISSN: 0257-8972
Status:Published
Keywords:Pack cementation Oxidation protection coatings Mo–9Si–8B
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:propulsion systems
DLR - Research area:Aeronautics
DLR - Program:L ER - Engine Research
DLR - Research theme (Project):L - Turbine Technologies
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > High Temperature and Functional Coatings
Deposited By: Watermeyer, Philipp
Deposited On:23 Nov 2015 13:03
Last Modified:31 Jul 2019 19:52

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