THE EFFECT OF V2O5 MELT INFILTRATION ON THE FAILURE OF THERMAL BARRIER COATINGS

The use of low quality fuel in land based driven turbine in Saudi Arabia usually results in hot corrosion attack (Type 1) due to the penetration of V2O5 into the existing micro pores and cracks on the top coat of thermal barrier coatings (TBCs). As a result of dissolution-precipitation reaction, 4-5...

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Bibliographic Details
Published in:Journal of engineering science & technology 2017-02, Vol.12 (2), p.318-332
Main Authors: ABBA ABDULHAMID ABUBAKAR, SYED SOHAIL AKHTAR
Format: Article
Language:English
Subjects:
Melt infiltrated reaction zone
Monoclinic phase
Phase field model
Tetragonal phase
Thermal barrier coating
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Summary:The use of low quality fuel in land based driven turbine in Saudi Arabia usually results in hot corrosion attack (Type 1) due to the penetration of V2O5 into the existing micro pores and cracks on the top coat of thermal barrier coatings (TBCs). As a result of dissolution-precipitation reaction, 4-5% volumetric expansion of the coating occurs due to the tetragonal-to-monoclinic (destabilization) transformation of Zirconia. In the current work, a Phase Field Model that estimates the kinetics of micro-structural evolution during the diffusional tetragonal-to-monoclinic phase transformation in the Melt Infiltrated Reaction Zone of the top coat at 900ºC is developed. The model is sequentiallycoupled with constitutive model in order to determine the resulting stress field developed in the top coat. The results show that localized stresses are developed due to the Zirconia-destabilization transformation, and the stresses are found to be higher at the corners and curvatures formed by inter-lamella connection of the micro-pores and micro-cracks.
ISSN:1823-4690