Preparation of Dense Al₂O₃ Film on 8YSZ Coating by Sol-Gel Method

Abstract:

The 8 wt.% yttria-stabilized zirconia (8YSZ) thermal barrier coatings (TBCs) are widely used to protect hot superalloy components of gas turbine and jet engine. However, Cracks and pores in the 8YSZ coating would accelerate the oxidation of the bondcoat alloy and the corrosion of 8YSZ topcoat by molten salts and finally result in permanent failure of the TBCs. Hence, in this work, a sol-gel spin-coating method was employed to prepare a dense α-Al₂O₃ film on the surface of air-plasma-sprayed 8YSZ coatings, in order to block the paths of cracks and pores while keeping the stress tolerance of 8YSZ coatings. The influences of the polyvinylpyrrolidone (PVP) and alumina content of the sol on the microstructure of the α-Al₂O₃ film were investigated. It is found that a sol with PVP addition amount of 50 mg/mL and alumina solid content of 10% let to the achievement of a compact α-Al₂O₃ film. The positive results in this work would inspire more efforts to prepare dense films on TBCs and therefore improve their performance under service conditions.

• Periodical: Solid State Phenomena (Volume 281)
• Pages: 465-471
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.281.465
• Online since: August 2018
• Authors: Min Wang, Zi Yuan Wang, Ya Jie Yuan, Wei Pan*
• Keywords: 8YSZ, Al₂O₃ Film, Sol-Gel

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