Paper Title:

Functionally Graded Thermal Barrier Coatings with Improved Reflectivity and High-Temperature Capability

Periodical Materials Science Forum (Volumes 631 - 632)
Main Theme Multiscale, Multifunctional and Functionally Graded Materials
Edited by Akira Kawasaki, Akinaga Kumakawa and Masayuki Niino
Pages 73-78
DOI 10.4028/www.scientific.net/MSF.631-632.73
Citation Robert Vassen et al., 2009, Materials Science Forum, 631-632, 73
Online since October 2009
Authors Robert Vassen, Holger Kassner, Alexandra Stuke, Daniel Emil Mack, Maria Ophelia D. Jarligo, Detlev Stöver
Keywords Ceramic Top Coat, Gas Turbine, Plasma Spraying, Reflective Coating, Thermal Barrier Coating (TBC)
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Conventional thermal barrier coating (TBC) systems consist of a duplex structure with a metallic bondcoat and a ceramic, heat isolative topcoat. In modern TBCs the ceramic topcoat is further divided into layers with different functions. One example is the double layer system in which conventional yttria stabilized zirconia (YSZ) is used as bottom and new materials as pyrochlores or perovskites are used as topcoat layers. These systems demonstrated an improved temperature capability compared to standard YSZ. Examples of such systems will be shown. In modern gas turbines the increased temperatures and gas pressures lead to an increased fraction of radiative heat flow. Coatings with increased reflectivity can be used to avoid the direct heating of the metallic substrates by this radiation. An effective method to produce such coatings is suspension plasma spraying. These reflective coatings are deposited on top of the TBC system and will lead to a further grading and improved performance of the coating.

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