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Reaction-bonded Al2O3 coatings for Al2O3/Al2O3 CMCs

Mechnich, Peter (2019) Reaction-bonded Al2O3 coatings for Al2O3/Al2O3 CMCs. 10th International Conference on High-temperature Ceramic Matrix Composites (HTCMC-10), 2019-09-22 - 2019-09-26, Bordeaux, Frankreich.

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Ceramic matrix composites based on Al2O3 fibers and porous Al2O3 matrices are being developed for various applications in harsh environments. Thermo-chemical degradation of Al2O3 is associated with hydroxylation in hot H2O-rich atmospheres and subsequent volatilization of Al-hydroxide species. This kind of degradation can effectively be reduced by recession-resistant environmental barrier coatings (EBC). A key issue for CMC is the relative low mechanical stability of the porous matrices, therefore CMC surfaces are prone to selective erosion in high-velocity gas streams, e.g. during coating by thermal spraying technologies. But also application of CMC without EBC may be limited due to low surface stability. Reaction-bonded Al2O3 coatings can effectively homogenize and stabilize CMC surfaces. Dispersions of Al2O3 and Al are deposited on the surface and fired in air where Al is oxidized and bonds together with Al2O3 to the CMC surface. Such coatings can be used as bond-coatings for thermally sprayed top coatings. On the other hand, stand-alone RBAO coatings promise a simple and cost-effective solution for CMC applications where outstanding H2O-stability, i.e. EBC functionality is less important than e.g. erosion resistance. A key to successful processing of RBAO coatings is the careful selection of raw materials and process parameters adapted to the respective CMC substrate.

Item URL in elib:https://elib.dlr.de/130304/
Document Type:Conference or Workshop Item (Speech)
Title:Reaction-bonded Al2O3 coatings for Al2O3/Al2O3 CMCs
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Mechnich, PeterUNSPECIFIEDhttps://orcid.org/0000-0003-4689-8197UNSPECIFIED
Date:October 2019
Refereed publication:No
Open Access:No
Gold Open Access:No
In ISI Web of Science:No
Keywords:CMC, RBAO
Event Title:10th International Conference on High-temperature Ceramic Matrix Composites (HTCMC-10)
Event Location:Bordeaux, Frankreich
Event Type:international Conference
Event Start Date:22 September 2019
Event End Date:26 September 2019
Organizer:LCTS Universität Bordeaux
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 - Combustion Chamber Technologies (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > Structural and Functional ceramics
Deposited By: Mechnich, Dr.rer.nat. Peter
Deposited On:21 Nov 2019 09:02
Last Modified:24 Apr 2024 20:33

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