EB-PVD alumina (Al2O3) as a top coat on 7YSZ TBCs against CMAS/VA infiltration: Deposition and reaction mechanisms.
Al2O3 was deposited as a top coat on a standard 7YSZ layer (or layers) by means of EB-PVD technique and the corresponding morphology of the Al2O3/7YSZ coatings was studied in detail. This multi-layer TBC system was tested against calcium-magnesium-aluminium-silicate (CMAS) recession by performing in...
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ftdlr:oai:elib.dlr.de:119740 2023-12-03T10:22:23+01:00 EB-PVD alumina (Al2O3) as a top coat on 7YSZ TBCs against CMAS/VA infiltration: Deposition and reaction mechanisms. Naraparaju, Ravisankar Pubbysetty, Raghu Praveen Mechnich, Peter Schulz, U. 2018-04 application/pdf https://elib.dlr.de/119740/ https://elib.dlr.de/119740/1/Authors%20version.pdf en eng Elsevier https://elib.dlr.de/119740/1/Authors%20version.pdf Naraparaju, Ravisankar und Pubbysetty, Raghu Praveen und Mechnich, Peter und Schulz, U. (2018) EB-PVD alumina (Al2O3) as a top coat on 7YSZ TBCs against CMAS/VA infiltration: Deposition and reaction mechanisms. Journal of the European Ceramic Society, 38 (9), Seiten 3333-3346. Elsevier. doi:10.1016/j.jeurceramsoc.2018.03.027 <https://doi.org/10.1016/j.jeurceramsoc.2018.03.027>. ISSN 0955-2219. Hochtemperatur-und Funktionsschutzschichten Struktur- und Funktionskeramik Zeitschriftenbeitrag PeerReviewed 2018 ftdlr https://doi.org/10.1016/j.jeurceramsoc.2018.03.027 2023-11-06T00:24:04Z Al2O3 was deposited as a top coat on a standard 7YSZ layer (or layers) by means of EB-PVD technique and the corresponding morphology of the Al2O3/7YSZ coatings was studied in detail. This multi-layer TBC system was tested against calcium-magnesium-aluminium-silicate (CMAS) recession by performing infiltration experiments for different time intervals from 5 min to 50 hours at 1250 ºC using two types of synthetic CMAS compositions and Eyjafjallajökull volcanic ash (VA) from Iceland. The results show that the studied EB-PVD Al2O3/7YSZ coatings react quickly with CMAS or VA melt and form crystalline spinel (MgAl2-xFexO4) and anorthite (CaAl2Si2O4) phases. The presence of Fe-oxide in the CMAS has been found to be key element in influencing the spinel formation which was proved to be more efficient against CMAS sealing in comparison to the Fe-free CMAS compositions. Even though a rapid crystallization was assured, shrinkage cracks in the EB-PVD alumina layer produced during the crystallization heat treatment have proven to be detrimental for the CMAS/VA infiltration resistance. To overcome these microstructural drawbacks, an additional alumina deposition method, namely reaction-bonded alumina oxide (RBAO), was applied on top of EB-PVD Al2O3. RBAO acts as a sacrificial layer forming stable reaction products inhibiting further infiltration. Article in Journal/Newspaper Eyjafjallajökull Iceland German Aerospace Center: elib - DLR electronic library Journal of the European Ceramic Society 38 9 3333 3346 |
institution |
Open Polar |
collection |
German Aerospace Center: elib - DLR electronic library |
op_collection_id |
ftdlr |
language |
English |
topic |
Hochtemperatur-und Funktionsschutzschichten Struktur- und Funktionskeramik |
spellingShingle |
Hochtemperatur-und Funktionsschutzschichten Struktur- und Funktionskeramik Naraparaju, Ravisankar Pubbysetty, Raghu Praveen Mechnich, Peter Schulz, U. EB-PVD alumina (Al2O3) as a top coat on 7YSZ TBCs against CMAS/VA infiltration: Deposition and reaction mechanisms. |
topic_facet |
Hochtemperatur-und Funktionsschutzschichten Struktur- und Funktionskeramik |
description |
Al2O3 was deposited as a top coat on a standard 7YSZ layer (or layers) by means of EB-PVD technique and the corresponding morphology of the Al2O3/7YSZ coatings was studied in detail. This multi-layer TBC system was tested against calcium-magnesium-aluminium-silicate (CMAS) recession by performing infiltration experiments for different time intervals from 5 min to 50 hours at 1250 ºC using two types of synthetic CMAS compositions and Eyjafjallajökull volcanic ash (VA) from Iceland. The results show that the studied EB-PVD Al2O3/7YSZ coatings react quickly with CMAS or VA melt and form crystalline spinel (MgAl2-xFexO4) and anorthite (CaAl2Si2O4) phases. The presence of Fe-oxide in the CMAS has been found to be key element in influencing the spinel formation which was proved to be more efficient against CMAS sealing in comparison to the Fe-free CMAS compositions. Even though a rapid crystallization was assured, shrinkage cracks in the EB-PVD alumina layer produced during the crystallization heat treatment have proven to be detrimental for the CMAS/VA infiltration resistance. To overcome these microstructural drawbacks, an additional alumina deposition method, namely reaction-bonded alumina oxide (RBAO), was applied on top of EB-PVD Al2O3. RBAO acts as a sacrificial layer forming stable reaction products inhibiting further infiltration. |
format |
Article in Journal/Newspaper |
author |
Naraparaju, Ravisankar Pubbysetty, Raghu Praveen Mechnich, Peter Schulz, U. |
author_facet |
Naraparaju, Ravisankar Pubbysetty, Raghu Praveen Mechnich, Peter Schulz, U. |
author_sort |
Naraparaju, Ravisankar |
title |
EB-PVD alumina (Al2O3) as a top coat on 7YSZ TBCs against CMAS/VA infiltration: Deposition and reaction mechanisms. |
title_short |
EB-PVD alumina (Al2O3) as a top coat on 7YSZ TBCs against CMAS/VA infiltration: Deposition and reaction mechanisms. |
title_full |
EB-PVD alumina (Al2O3) as a top coat on 7YSZ TBCs against CMAS/VA infiltration: Deposition and reaction mechanisms. |
title_fullStr |
EB-PVD alumina (Al2O3) as a top coat on 7YSZ TBCs against CMAS/VA infiltration: Deposition and reaction mechanisms. |
title_full_unstemmed |
EB-PVD alumina (Al2O3) as a top coat on 7YSZ TBCs against CMAS/VA infiltration: Deposition and reaction mechanisms. |
title_sort |
eb-pvd alumina (al2o3) as a top coat on 7ysz tbcs against cmas/va infiltration: deposition and reaction mechanisms. |
publisher |
Elsevier |
publishDate |
2018 |
url |
https://elib.dlr.de/119740/ https://elib.dlr.de/119740/1/Authors%20version.pdf |
genre |
Eyjafjallajökull Iceland |
genre_facet |
Eyjafjallajökull Iceland |
op_relation |
https://elib.dlr.de/119740/1/Authors%20version.pdf Naraparaju, Ravisankar und Pubbysetty, Raghu Praveen und Mechnich, Peter und Schulz, U. (2018) EB-PVD alumina (Al2O3) as a top coat on 7YSZ TBCs against CMAS/VA infiltration: Deposition and reaction mechanisms. Journal of the European Ceramic Society, 38 (9), Seiten 3333-3346. Elsevier. doi:10.1016/j.jeurceramsoc.2018.03.027 <https://doi.org/10.1016/j.jeurceramsoc.2018.03.027>. ISSN 0955-2219. |
op_doi |
https://doi.org/10.1016/j.jeurceramsoc.2018.03.027 |
container_title |
Journal of the European Ceramic Society |
container_volume |
38 |
container_issue |
9 |
container_start_page |
3333 |
op_container_end_page |
3346 |
_version_ |
1784270305415397376 |