Degradation of Protective Al - Si Coatings during Exploitation of Gas Turbine Blades

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Abstract:

Diffusion Al-Si coatings are often used to protect rotor blades of aircraft engines against high-temperature corrosion in environments containing sulfur compounds. Besides other microstructural changes, the degradation of AlSi layers can be indicated by an increasing amount of surface oxide phases and changes in parameters of the layer geometry. In practice, the timetemperature area beyond a critical temperature of the outgoing gas is used as an empirical exploitation parameter D indicating a degradation level. The efficiency of such approach was investigated by analyzing degradation features in the surface layers of rotor blades after exploitations corresponding to different values of D. Determined simple relationships between the relative thickness of degraded layer and the parameter D verify the methodology and yield its clear geometrical interpretation. However, this method fails to provide reasonable information in case when the gas is burning outside the combustion chamber due to a sudden decrease of turbine revolutions.

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Periodical:

Materials Science Forum (Volumes 567-568)

Pages:

309-312

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Online since:

December 2007

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© 2008 Trans Tech Publications Ltd. All Rights Reserved

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[1] Data of Turbine-design department HTC-AED a. s. Považská Bystrica, Slovakia.

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[2] L. Swadźba, B. Formanek, A. Maciejny: Corrosion damage and regeneration of aluminide coatings on aircraft turbine blades. Materials Science and Engineering A. Vol. 120-121 (1989), pp.407-412.

DOI: 10.1016/0921-5093(89)90794-6

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[3] L. Swadźba, A. Maciejny, B. Formanek: Microstructure and resistance to cracking of modified Al-Si and Al-Cr diffusion on ŽS6K nickel-based superalloys. Surface and Coatings Technology. Vol. 54-55 (1992), pp.84-90.

DOI: 10.1016/s0257-8972(09)90032-9

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[4] M. Kianicová: Fireproof diffusive coating degradation in consequence of short-time operating temperature exceeding. PhD Thesis, AD University in Trencin, (2006).

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