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UNDERSTANDING THE PRESENCE OF CASO4 WITHIN CMAS AND ITS EFFECT ON THE INFILTRATION BEHAVIOUR IN EB-PVD 7YSZ

Naraparaju, Ravisankar and Schulz, U. and Mechnich, Peter and Mondragón Rodríguez, G.C. (2014) UNDERSTANDING THE PRESENCE OF CASO4 WITHIN CMAS AND ITS EFFECT ON THE INFILTRATION BEHAVIOUR IN EB-PVD 7YSZ. TBC conference, 23-27th June, Irsee, Germany.

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Abstract

Infiltration of CaO-MgO-Al2O3-SiO2 (CMAS) in TBCs is an issue of concern for the aeronautical industry. From the existing research it is known that as soon as CMAS melts it infiltrates the TBC structure, chemically attacks the TBC, changes its phase composition and ultimately leads to the spallation of the TBC. Few investigations have shown the presence of anhydrite (CaSO4) within CMAS deposits. These investigations could not provide a complete understanding of the presence and the effect of CaSO4 on CMAS induced TBCs damage in this study. A systematic approach in understanding the effect of CaSO4 in CMAS has been taken. Five different CMAS compositions with and without CaSO4 were synthesized in the laboratory and their infiltration behaviours were investigated by depositing them on EB-PVD 7YSZ samples and subsequent heating at 1225 and1250°C. In addition, mass spectroscopy was applied on CaSO4 containing CMAS and the vaporization behaviour of sulphur was studied at high temperature. XRD was applied on the molten CMAS compositions and differences in phase formation due to the presence of CaSO4 were analysed. Based on this information, it is proved that sulphur which was present in the form of anhydrite evaporates as SO3 during the high temperature heating and extra CaO adds to the CMAS composition. This CaO-enriched CMAS is found to be more destructive than the initial CMAS. Hence it can be emphasised that CaSO4 presence in CMAS has no direct effect on the infiltration, but rather an indirect effect in changing the CMAS composition.

Item URL in elib:https://elib.dlr.de/92833/
Document Type:Conference or Workshop Item (Poster)
Additional Information:This work is reviewd
Title:UNDERSTANDING THE PRESENCE OF CASO4 WITHIN CMAS AND ITS EFFECT ON THE INFILTRATION BEHAVIOUR IN EB-PVD 7YSZ
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Naraparaju, Ravisankarravisankar.naraparaju (at) dlr.deUNSPECIFIED
Schulz, U.UNSPECIFIEDUNSPECIFIED
Mechnich, PeterUNSPECIFIEDUNSPECIFIED
Mondragón Rodríguez, G.C.guillermo.mondragon-rodriguez (at) dlr.deUNSPECIFIED
Date:2014
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:CMAS, EB-PVD and YSZ
Event Title:TBC conference
Event Location:Irsee, Germany
Event Type:international Conference
Event Dates:23-27th June
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:01 Dec 2014 13:56
Last Modified:09 Apr 2015 13:34

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