Lifetime investigations of new TBC materials

Kurzfassung

Lower thermal conductivity and high temperature stability are the two properties which are highly desired from ceramic top coat materials in TBC systems. Gadolinium Zirconate, Gd2Zr2O7, (GdZ) and Dyprosia Stabilized Zirconia (DySZ) are two of the candidate materials with such properties and consequently the TBC system would be able to work at higher turbine inlet temperature (TIT) or the lifetime can be increased. In the present study, life time measurements are done for the single and double layered Electron Beam Physical Vapor Deposition (EB-PVD) GdZ and DySZ samples by thermal-cycling tests. Both single and double layered samples of GdZ and DySZ have shown similar or better lifetimes than the standard YSZ samples. However, single layered TBCs showed better lifetime results than the respective double layers. In this study, changes in the microstructure, diffusion of elements and sintering of TBC materials with aging are observed.