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3732 |
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Properties and performance of high porosity YSZ and DySZ thermal barrier coatings |
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Wyszomir Janikowski* / University West / The University of Manchester, Sweden Nicholas Erb/ The University of Manchester, United Kingdom Nicholas Curry/ University West, Sweden Lars Östergren/ GKN Aerospace Engine Systems, Sweden Nicolaie Markocsan/ University West, Sweden Mitch Dorfman/ Sulzer Metco, USA Xin-Hai Li/ Siemens Industrial Turbomachinery AB, Sweden |
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Recently developed dysprosia-stabilised zirconia (DySZ) coatings have shown improved insulative and thermal cyclic performance. Zirconia powders stabilised with yttria or dysprosia were sprayed with air plasma spraying (APS). A design of experiments towards maximum porosity was created so that levels of 25% were achieved. High temperature durability was evaluated by thermally cycling the samples at 1100°C. Furthermore, X-ray diffraction (XRD) analysis provided information on phases present and their stability. Laser flash technique was used to assess thermal conductivity of the coatings over the complete range of operational temperatures. Tests were carried out on as-sprayed samples and samples exposed to 1150°C for times up to 400h. The microstructural evolution of the heat treated samples was examined with a scanning electron microscope (SEM) aided by image analysis software. Dilatometry of free standing coatings annealed at 1400°C served to quantify sintering behaviour. |