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Investigation of CMAS Resistance of Sacrificial Suspension Sprayed Alumina Topcoats on EB-PVD 7YSZ Layers

Mikulla, Christoph and Naraparaju, Ravisankar and Schulz, Uwe and Toma, Filofteia-Laura and Barbosa, Maria and Leyens, Christoph (2019) Investigation of CMAS Resistance of Sacrificial Suspension Sprayed Alumina Topcoats on EB-PVD 7YSZ Layers. In: Proceedings of the International Thermal Spray Conference, pp. 79-85. ASM International. International Thermal Spray Conference and Exposition (ITSC 2019), 26.-29. Mai 2019, Yokohama, Japan. ISBN 978 1 5108 8800 5.

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Official URL: http://www.proceedings.com/49258.html


Molten calcium-magnesium-aluminum-silicate (CMAS) mineral particles cause significant degradation of thermal barrier coatings (TBCs) in aero-engines. One approach to protect the TBC coating against the CMAS attack is the application of a sacrificial coating on top of the TBC coating. In this work sacrificial Al2O3 coatings were deposited on top of EB-PVD 7YSZ layers using suspension thermal spraying starting from an aqueous Al2O3 suspension. Spray parameters were varied in order to produce sacrificial topcoats with two different microstructures and porosities levels. The coating systems were tested under CMAS attack by performing short and long-time infiltration tests at 1250 °C. It was found out that the porosity and morphology of Al2O3 coatings strongly influenced the CMAS infiltration kinetics and the formation of various phases. CMAS mitigation depended on the interaction between the coating morphology which rules the driving force for infiltration, as well as on the reaction speed between alumina and the CMAS deposit.

Item URL in elib:https://elib.dlr.de/129505/
Document Type:Conference or Workshop Item (Speech)
Title:Investigation of CMAS Resistance of Sacrificial Suspension Sprayed Alumina Topcoats on EB-PVD 7YSZ Layers
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Mikulla, ChristophChristoph.Mikulla (at) dlr.deUNSPECIFIED
Naraparaju, RavisankarRavisankar.Naraparaju (at) dlr.deUNSPECIFIED
Schulz, UweUwe.Schulz (at) dlr.dehttps://orcid.org/0000-0003-0362-8103
Toma, Filofteia-LauraFraunhofer-Institut für Werkstoff und Strahltechnik IWSUNSPECIFIED
Barbosa, MariaFraunhofer-Institut für Werkstoff und Strahltechnik IWSUNSPECIFIED
Leyens, ChristophTU DresdenUNSPECIFIED
Date:August 2019
Journal or Publication Title:Proceedings of the International Thermal Spray Conference
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:No
Page Range:pp. 79-85
EditorsEmailEditor's ORCID iD
Azarmi, FardadNorth Dakota State UniversityUNSPECIFIED
Publisher:ASM International
ISBN:978 1 5108 8800 5
Keywords:Thermal barrier Coating, CMAS, Wärmedämmschicht, 7YSZ, Al2O3, sacrificial coating, Opferschicht, Suspension spraying, SHVOF
Event Title:International Thermal Spray Conference and Exposition (ITSC 2019)
Event Location:Yokohama, Japan
Event Type:international Conference
Event Dates:26.-29. Mai 2019
Organizer:ASM International
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 (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > High Temperature and Functional Coatings
Deposited By: Mikulla, Christoph
Deposited On:15 Nov 2019 15:16
Last Modified:15 Nov 2019 15:16

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