Fonctionnalisation de barrières thermiques aéronautiques YSZ issues de la voie sol-gel : mesure de température et diagnostic de l'endommagement par fluorescence

Abstract : The aim of this work is to develop and study yttria stabilised zirconia (ZrO2 + 9.8at% Y2O3, YSZ) based thermal barrier coating (TBC) « sensor » systems deposited by a dip coating sol-gel process, and dedicated to temperature measurement and to the monitoring of damaging occuring within the thickness of the coatings, using fluorescence thermometry methods. These methods are based on the monitoring of the fluorescence properties of photoluminescent activators from the trivalent lanthanide ions group (Ln3+), such as samarium Sm3+, europium Eu3+, dysprosium Dy3+, erbium Er3+ and thulium Tm3+. These activators are directly incorporated into the zirconia YSZ host matrix lattice, which is semi-transparent at their emission wavelengths mainly falling in the visible range. An experimental set up was especially developped for the application of these methods. The characterisation of the different YSZ:Ln3+ powders synthesized by a sol-gel process allowed to optimise the compositions, and thus maximize the fluorescence signal intensity while avoidind any alteration of the zirconia crystal structure required from for a TBC material. The sol-gel dip coating process allowed to deposit functionalised multilayer TBC prototypes integrating up to three fluorescent layers with distinct emission wavelengths distributed throughout the thickness. Such coating architectures allow, with the fluorescence thermometry methods identified, to optically probe the coating across the whole thickness for future applications aiming to determine the thermal gradient in TBCs. Functionalised TBCs containing pre-calibrated delamination defects at the metal/ceramic interface were also used to compare the interest of the reflectance enhanced fluorescence method and an IR thermography method for early monitoring of TBC spallation. At last, the potential offered by YSZ:Ln3+ powders as thermal history sensors alternative to temperature sensitive paints was also investigated.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-01304767
Contributor : Abes Star <>
Submitted on : Wednesday, April 20, 2016 - 12:11:41 PM
Last modification on : Tuesday, February 25, 2020 - 11:44:05 AM
Long-term archiving on: Thursday, July 21, 2016 - 12:31:28 PM

File

CopinEtienneDiff.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01304767, version 1

Citation

Etienne Copin. Fonctionnalisation de barrières thermiques aéronautiques YSZ issues de la voie sol-gel : mesure de température et diagnostic de l'endommagement par fluorescence. Mécanique des matériaux [physics.class-ph]. Ecole des Mines d'Albi-Carmaux, 2015. Français. ⟨NNT : 2015EMAC0011⟩. ⟨tel-01304767⟩

Share

Metrics

Record views

996

Files downloads

566