A thermodynamic study of the influence of the Al2O3 content on the CaO-SiO2-YO1.5 system

Wednesday, February 7, 2024 - 16:57

In the context of the corrosion of aeronautical turbine blades corrosion, the article presents the influence of the alumina proportion on the extent of the liquid field (i.e. the corrosive medium).

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Abstract

In aircraft engines applications, the interactions between rare earth silicates (mainly yttrium silicates) used as Environmental Barrier Coatings (EBCs) on turbine blades and liquid calcium-magnesium-aluminosilicates (CMAS) due to the particles ingested by the engines may lead to severe damages at high temperature. Due to the large range of composition of CMAS, simplified model systems must be used to have a good comprehension of the thermochemical phenomena leading to degradation. The interaction between ceramics and CMAS can lead to the precipitation of phases as apatite Ca2Y8(SiO4)6O2 and cyclosilicate Ca₃Y₂(Si₃O₉)₂ which might provide protection to the EBC. However, their thermodynamic stability depends on many parameters. In the present work, the influence of alumina Al₂O₃ addition to the ternary system CaO-SiO₂-YO_1.5 has been studied in order to verify the equilibrium with the liquid field at 1300°C.

Authors

J. Bonnal, S. Mermoul, C. Petitjean, P.J Panteix, D. Bonina, C. Gendarme, S. Arnal, M. Vilasi

References

Journal of the European Ceramic Society xxxx (2024) xxxxx

DOI

https://doi.org/10.1016/j.jeurceramsoc.2024.01.072