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1495 |
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Spraying process, microstructure and relaxation stress behavior of cylindrical stand alone YSZ coatings with and without segmentation cracks |
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Matthias Karger / Forschungszentrum Jülich, Germany Christopher A. Petorak / Purdue University, School of Materials Engineering, IN 47907, USA Rodney Trice/ PurdueTrice University, School of Materials Engineering, IN 47907, USA Robert Vaßen/ Forschungszentrum Jülich GmbH, Institut für Energieforschung IEF-1, Germany Detlev Stöver/ Forschungszentrum Jülich GmbH, Institut für Energieforschung IEF-1, Germany |
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Segmentation cracked coatings are promising candidates for thermal barrier coatings (TBC) with high strain tolerances. With atmospheric plasma spraying (APS), cylindrical stand-alone YSZ coatings with and without segmentation cracks were fabricated. The diameter of the tubes was 10 mm, and the thickness of the coatings amounted to 1 mm. The segmentation crack densities were in the range of 3,5 cracks/mm, while the porosity was for all coatings between 5% and 7%. Further details of the spraying process and the obtained microstructures will be given and discussed. The samples were tested in an uniaxial high temperature compression rig to measure the stress relaxation. The comparison of the stress relaxation measurements yielded a different behaviour of segmented and non-segmented coatings with advantages for the cracked ones. It was observed that the cracks increase the resistance to stress relaxation. |