WEB Advanced coating technologies for thermal barrier coatings in gas turbinesThursday (24.09.2020) 11:20 - 11:50 F: Functional Materials, Surfaces, and Devices 1 Part of:
In modern gas turbines, both for stationary and aero applications, thermal barrier coatings (TBCs) are essential to guarantee high efficiency and durability. A frequently used deposition technology is thermal spray which offers the possibility to manufacture a wide range of different microstructures. In addition to the well-established atmospheric plasma spraying (APS), new technologies, which allow columnar architectures and hence high strain tolerance similar to EB-PVD type coatings, attract a lot of interest. The presentation will show results for coatings made by suspension plasma spraying (SPS) and plasma spray physical vapor deposition (PS-PVD) and compare these with APS coatings.
In addition to the deposition technology also the coating material is studied intensively. Yttria stabilized zirconia (YSZ) is still the state of the art material although it is stated, that its long-term operation temperature is limited to 1200°C. Here an overview is given with respect to new TBC materials and also the temperature capability of YSZ.
Recently, the use of ceramic matrix composites (CMCs) as structural materials in gas turbines is of increasing importance. Also these materials need protective coatings due to their susceptibility against water vapor corrosion. These so-called environmental barrier coatings (EBCs) are typically produced by thermal spray, mainly APS. Here recent developments are shown.
Finally, the attack by CaMgAl-silicate (CMAS, the major constituent of volcanic ash), a severe degradation mechanism especially in aero engines, will be discussed. Results of the degradation in a gradient test facility of standard APS TBCs but also other advanced coatings will be presented.