Untersuchung der Rissausbreitung in Wärmedämmschichtsystemen unter thermomechanischer Beanspruchung

Thermal barrier coatings (TBCs) are nowadays widely applied in gas turbines and airplane engines to allow higher operating temperatures and thus higher efficiencies. The porous ceramic top coating (typically yttria stabilized zirconia, YSZ) in conjunction with active cooling of the base material leads to the formation of a thermal gradient between hot gas and turbine component. Consequently, the gas temperature can be raised without reaching critical temperatures in the component base material.

However, the TBC may fail (i.e. crack or spall) during operation as a result of several degradation mechanisms, such as, micro-crack growth induced by thermal and/or mechanical loading or chemical degradation. Currently there is a considerable deficit in the knowledge of the evolution of crack initiation and crack growth up to macroscopic delamination. Therefore it is necessary to develop a deeper understanding of the damage evolution processes under isothermal, thermo-cyclic, but also thermo-mechanical loading conditions.

The aim of this work is to develop a TBC lifetime model for currently used atmospheric plasma sprayed (APS) thermal barrier coating systems based on the mechanical strain necessary to cause failure of the coating.

Das IGF-Vorhaben 14873 N der Forschungsvereinigung Verbrennungskraftmaschinen e.V., Lyoner Straße 2, 60528 Frankfurt am Main, wurde über die AiF im Rahmen des Programms zur Förderung der industriellen Gemeinschaftsforschung und -entwicklung (IGF) vom Bundesministerium für Wirtschaft und Technologie aufgrund eines Beschlusses des Deutschen Bundestages gefördert.