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Erosion resistance of CMAS infiltrated sacrificial suspension sprayed alumina top layer on EB-PVD 7YSZ coatings

Steinberg, Lars and Mikulla, Christoph and Naraparaju, Ravisankar and Toma, Filofteia- Laura and Großmann, Holger and Schulz, Uwe and Leyens, C. (2019) Erosion resistance of CMAS infiltrated sacrificial suspension sprayed alumina top layer on EB-PVD 7YSZ coatings. WEAR, 438-39, p. 203064. Elsevier. DOI: 10.1016/j.wear.2019.203064 ISSN 0043-1648

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Abstract The development of CMAS (CaO-MgO-Al2O3-SiO2) -resistant thermal barrier coatings is an urgent issue, as the operating temperatures of aero-engines exceed the melting point of the CMAS. Application of alumina as top layer on 7YSZ coatings has shown promising CMAS resistance behavior. It reacts with the CMAS and crystallizes into new stable phases, which seals the CMAS penetration paths in the top layer to save the underlying 7YSZ layer from infiltration. This paper deals with the study of the erosion behavior of porous thermally sprayed Al2O3 sacrificial layer on top of EB-PVD 7YSZ coatings before and after the CMAS infiltration and investigates the combined erosion/corrosion regime. The TBC system has been infiltrated with three different CMAS compositions having a different Ca/Si ratio which resulted in different reaction scenarios and products. The change in the erosion behavior of the coating system as a function of CMAS infiltration depth was investigated and an erosion model has been proposed. The key factors that dictate the erosion resistance of such alumina layers were found to be the thickness and morphology of the reaction layer, the porosity of the non-reacted alumina layer underneath the reaction layer as well as the coating adhesion mechanism between alumina and 7YSZ.

Item URL in elib:https://elib.dlr.de/130390/
Document Type:Article
Title:Erosion resistance of CMAS infiltrated sacrificial suspension sprayed alumina top layer on EB-PVD 7YSZ coatings
AuthorsInstitution or Email of AuthorsAuthors 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
Leyens, C.Technische Universität DresdenUNSPECIFIED
Date:20 September 2019
Journal or Publication Title:WEAR
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:Yes
DOI :10.1016/j.wear.2019.203064
Page Range:p. 203064
Keywords:TBC; solid particle erosion; CMAS; alumina; suspension plasma spraying; erosion testing
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: Naraparaju, Dr Ravisankar
Deposited On:11 Nov 2019 18:20
Last Modified:11 Nov 2019 18:20

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