Molten sodium corrosion of laser surface remelted yttria-stabilized zirconia thermal barrier coatings

[Display omitted] •Laser-remelted YSZ TBCs showed chemical inertness in molten sodium.•LSR produced a dense, columnar and smooth surface architecture in YSZ TBCs.•Vertical segmented cracks allowed molten sodium infiltration and disintegration at non-remelted interfaces.•The corrosion mechanism of LS...

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Bibliographic Details
Published in:Corrosion science 2021-10, Vol.191, p.109740, Article 109740
Main Authors: Varghese, Paulson, Vetrivendan, E., Vaishnavi Krupa, B.R., Shukla, Prabhat Kumar, Gupta, Ram Kishor, Hemant Rao, E., Puppala, Ganesh, Ningshen, S.
Format: Article
Language:English
Subjects:
A: Ceramic
A: Stainless Steel
B: SEM
B: XRD
Breeder reactors
C: Molten sodium
C: Reactor conditions
Coatings
Corrosion
Fast breeder
Liquid metals
Melting
Microstructure
Sodium
Spallation
Structural integrity
Thermal barrier coatings
Yttria-stabilized zirconia
Yttrium oxide
Zirconium dioxide
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Summary:[Display omitted] •Laser-remelted YSZ TBCs showed chemical inertness in molten sodium.•LSR produced a dense, columnar and smooth surface architecture in YSZ TBCs.•Vertical segmented cracks allowed molten sodium infiltration and disintegration at non-remelted interfaces.•The corrosion mechanism of LSR YSZ in molten sodium is primarily of physical decohesion at weak boundaries. Liquid-metal corrosion in molten sodium is a significant issue to Thermal Barrier Coatings (TBCs) proposed for in-core fast breeder reactor applications. In this study, the viability of attenuating molten sodium corrosion of plasma-sprayed yttria-stabilized zirconia TBCs is investigated by microstructure re-engineering using Laser Surface Remelting (LSR). LSR produced a smooth and dense surface with columnar microstructure and segmented vertical cracks. At the onset of molten sodium corrosion, the remelted layer retained structural integrity but exhibited localized corrosive attack along the surface-network cracks. However, on further exposure, the vertical cracks lead to molten sodium infiltration down the non-remelted layers, causing corrosive damage and spallation of coating.
ISSN:0010-938X
1879-0496
DOI:10.1016/j.corsci.2021.109740