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Comparison of the performance of EB-PVD GZO and Yttria rich zirconate coatings against CMAS infiltration

Naraparaju, Ravisankar and Mikulla, Christoph and Mechnich, Peter and Kelm, Klemens and Schulz, Uwe and Gomez Chavez, Juan J (2022) Comparison of the performance of EB-PVD GZO and Yttria rich zirconate coatings against CMAS infiltration. ICACC, 2022-01-23 - 2022-01-28, Daytona Beach, USA.

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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/191150/
Document Type:Conference or Workshop Item (Speech)
Title:Comparison of the performance of EB-PVD GZO and Yttria rich zirconate coatings against CMAS infiltration
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Naraparaju, RavisankarUNSPECIFIEDhttps://orcid.org/0000-0002-3944-1132UNSPECIFIED
Mikulla, ChristophUNSPECIFIEDhttps://orcid.org/0000-0001-9367-8301UNSPECIFIED
Mechnich, PeterUNSPECIFIEDhttps://orcid.org/0000-0003-4689-8197UNSPECIFIED
Schulz, UweUNSPECIFIEDhttps://orcid.org/0000-0003-0362-8103UNSPECIFIED
Date:January 2022
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:No
Keywords:EB-PVD thermal barrier coatings CMAS attack Infiltration kinetics Microstructures Reaction mechanism Phase formation
Event Title:ICACC
Event Location:Daytona Beach, USA
Event Type:international Conference
Event Start Date:23 January 2022
Event End Date:28 January 2022
Organizer:American Ceramic Society
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
Institute of Materials Research > Administrativ-Technische Betriebsleitung / Mikroanalytik und Metallographie
Deposited By: Naraparaju, Dr Ravisankar
Deposited On:05 Dec 2022 09:24
Last Modified:24 Apr 2024 20:52

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