Abstract No.:
2791

 Scheduled at:
Thursday, September 29, 2011, Saal B2.2 2:00 PM
Characterization & Testing 4


 Title:
The influence of CMAS attack on the lifetime of thermal barrier coatings

 Authors:
Tanja Steinke* / Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung (IEK-1), , Germany
Maria Ophelia Jarligo / Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung (IEK-1), Germany
Daniel Emil Mack/ Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung (IEK-1), Germany
Robert Vaßen/ Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung (IEK-1), Germany
Detlev Stöver/ Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung (IEK-1), Germany

 Abstract:
Oxide compounds basically composed of calcium, magnesium, aluminum and silicon also known as CMAS, can be deposited on the surface of the thermal barrier coatings (TBC) of gas turbine blades. These compounds have been found to aggressively degrade the TBC, hence affecting the thermomechanical properties of the underlying component. Detailed investigation on the interaction of CMAS and the atmospheric plasma sprayed (APS) yttria stabilized zirconia (YSZ) TBC was performed in a burner rig test facility under thermal gradient cycling conditions and at the same time CMAS deposition. This novel and unique test approach promises a coating screening and characterization test under service conditions. Variable exposure times at 1250°C/1050°C surface/substrate temperatures were applied. The lifetime of the TBC was indicated by the number of thermal cycles when visible spallation of the TBC layer occurred. X-ray crystallography and microstructural analyses were then conducted on the cycled samples to determine the effect of thermochemical interactions. The results of the investigation will shed light on the extent of APS TBC degradation due to CMAS attack at high temperatures.

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