This title appears in the Scientific Report :
2008
Please use the identifier:
http://hdl.handle.net/2128/3106 in citations.
Optimierung der Reflektivität keramischer Wärmedämmschichten aus Yttrium-teilstabilisiertem Zirkoniumdioxid für den Einsatz von metallischen Komponenten in Gasturbinen
Optimierung der Reflektivität keramischer Wärmedämmschichten aus Yttrium-teilstabilisiertem Zirkoniumdioxid für den Einsatz von metallischen Komponenten in Gasturbinen
Thermal barrier coatings (TBC) are employed to thermally isolate metallic components in gas turbines. They allow for an increase of the life-time of components subjected to high thermal stress and make it possible to increase the temperature of the incoming gas, which increases the efficiency or the...
Saved in:
Personal Name(s): | Stuke, Alexandra (Corresponding author) |
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Contributing Institute: |
Werkstoffsynthese und Herstellungsverfahren; IEF-1 |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
2008
|
Physical Description: |
X, 201 S. |
Dissertation Note: |
Bochum, Univ., Diss., 2007 |
ISBN: |
978-3-89336-515-9 |
Document Type: |
Book Dissertation / PhD Thesis |
Research Program: |
Rationelle Energieumwandlung |
Series Title: |
Schriften des Forschungszentrums Jülich : Energie & Umwelt / Energy & Environment
4 |
Subject (ZB): | |
Link: |
OpenAccess |
Publikationsportal JuSER |
Thermal barrier coatings (TBC) are employed to thermally isolate metallic components in gas turbines. They allow for an increase of the life-time of components subjected to high thermal stress and make it possible to increase the temperature of the incoming gas, which increases the efficiency or the turbines. With the constant increase of process temperatures, thermal load increases and so does the requirement on the ceramic material. In particular gas turbine blades and vanes are subjected to thermal radiation emitted by surrounding heat shields and gas due to high temperatures of the incoming gas. However, the currently empolyed material yttria partially stabilized zirconia (YSZ) shows a great transmissicity of thermal radiation within a lorge range of wavelengths. This leads to an increase of temperature of the contact area with the metal, decreasing the life-time of the TBC system. Within the scope of this wirk, the reflectivity of plasma-sprayed zirconia coatings could be otimized, which leads to a better insulating property of the coating against thermal radiation. This was achieved by optimizing the scattering of the coating via midifying its layer morphology. By introducing additional pores and Al$_{2}$O$_{3}$ particles, the number of scattering centers could be raised and the amount of scattering could be increased substantially. By means of optical measurements of reflectivity and transmissivity, it could be shown that the total porosity plays a key role in the increase of scattering and that optical properties are controllable by manipulating the microstructure. Via extending the spray distance of employing suspernsion plasma spraying for assembling the zirconia coatings, the porosity could be increased to 20 and 40 % respectively. Furthermore, suspension plasma-sprayed coatings achieved the highest reflectivity (95 %), and its transmissivity could be reduced from 15 to 3 % in comparison with atmospheric plasma-sprayed coatings. Using angular-dependent optical measurements, the applicability of a two-flux model, [...] |