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Comparative study of EB-PVD gadolinium-zirconate and yttria-rich zirconia coatings performance against Fe-containing calcium-magnesium-aluminosilicate (CMAS) infiltration

Chavez, Juan J. Gomez and Naraparaju, Ravisankar and Mikulla, Christoph and Mechnich, Peter and Kelm, Klemens and Ramana, C.V. and Schulz, Uwe (2021) Comparative study of EB-PVD gadolinium-zirconate and yttria-rich zirconia coatings performance against Fe-containing calcium-magnesium-aluminosilicate (CMAS) infiltration. Corrosion Science, 190, p. 109660. Elsevier. ISSN 0010-938X.

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Official URL: http://dx.doi.org/10.1016/j.corsci.2021.109660

Abstract

This detailed study compare and contrast the calcium-magnesium-aluminosilicate (CMAS) infiltration resistance behavior of electron-beam physical vapor deposition (EB-PVD) produced gadolinium zirconate (GZO) and yttria rich zirconia (65YZ, 65 wt % Y2O3 rest zirconia) coatings. The infiltration kinetics, as well as the stability and protective nature of different reaction products, was studied by performing long term infiltration tests (up to 50 h) at 1250 °C. The results reveal that for the specific microstructures used in this study, 65YZ has a higher infiltration resistance and forms a thinner reaction layer compared to GZO. The analysis indicates that the better performance of 65YZ is associated with a synergetic reaction mechanism, which includes the formation of Carich apatite and a uniform layer of a garnet phase. The formation of apatite requires more rare-earth (RE) in the case of GZO than its 65YZ counterpart, meaning that more Gd would be dissolved before forming apatite crystals, which leads to higher consumption of the GZO layer compared to that of 65YZ. The implications of these mechanisms are discussed in detail concerning the tendency of garnet formation, equilibration of the apatite phase with Ca and RE content, and the effects of the reduction in viscosity due to the RE dissolution into the glass. However, microstructural differences in the coatings used in this study might also affect the diverging infiltration resistance and reaction kinetics and need to be considered

Item URL in elib:https://elib.dlr.de/145002/
Document Type:Article
Title:Comparative study of EB-PVD gadolinium-zirconate and yttria-rich zirconia coatings performance against Fe-containing calcium-magnesium-aluminosilicate (CMAS) infiltration
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Chavez, Juan J. GomezUNSPECIFIEDUNSPECIFIED
Naraparaju, RavisankarUNSPECIFIEDUNSPECIFIED
Mikulla, ChristophUNSPECIFIEDUNSPECIFIED
Mechnich, PeterUNSPECIFIEDUNSPECIFIED
Kelm, KlemensUNSPECIFIEDUNSPECIFIED
Ramana, C.V.UNSPECIFIEDUNSPECIFIED
Schulz, UweUNSPECIFIEDUNSPECIFIED
Date:2021
Journal or Publication Title:Corrosion Science
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:190
Page Range:p. 109660
Publisher:Elsevier
ISSN:0010-938X
Status:Published
Keywords:EB-PVD thermal barrier coatings, CMAS attack, Infiltration kinetics, Microstructures, Reaction mechanism, Phase formation
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Clean Propulsion
DLR - Research area:Aeronautics
DLR - Program:L CP - Clean Propulsion
DLR - Research theme (Project):L - Advanced Materials and New Manufacturing Technologies
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > High Temperature and Functional Coatings
Institute of Materials Research > Structural and Functional ceramics
Deposited By: Naraparaju, Dr Ravisankar
Deposited On:08 Nov 2021 10:00
Last Modified:08 Nov 2021 10:00

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