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4708 |
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Wednesday, May 11, 2016, Room 3H + 3I + 3J 10:00 AM Power Generation I |
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Thermal fatigue failure of thermal barrier coatings with a high-Cr MCrAlY bond coat |
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Kang Yuan* / BGRIMM Technology Group, P.R. China Yueguang Yu / Beijing General Research Institute of Mining and Metallurgy, China Krishna Praveen Jonnalagadda/ Linkoping University, Sweden Ru Lin Peng/ Linkoping University, Sweden Xin-Hai Li/ Siemens Industrial Turbomachinery AB, Sweden Jie Shen/ Beijing General Research Institute of Mining and Metallurgy, China Xiaojuan Ji/ Beijing General Research Institute of Mining and Metallurgy, China |
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Thermal barrier coatings (TBCs) have been widely used in gas turbine fields. In this study, TBC was air-plasma sprayed (APS) on Hastelloy X substrate. The TBC consisted of a high-Cr NiCoCrAlY bond coat (BC) and a high-purity nanocrystallized yttria-stabilized zirconia (YSZ) top coat (TC). The samples were thermally cycled between 100 ºC and 1100 ºC with 1 hour dwell time at 1100 ºC. The thermal fatigue failure of the TBC was investigated by microstructure analysis. It was observed that chromia and Cr-rich spinel oxides were formed above an alumina layer at the TC-BC interface. Cracks were formed mainly in or near such Cr-rich oxides. The development of the oxide layers was therefore studied in detail including by using a developed oxidation-diffusion model. In addition, the influence of substrate blasting and BC roughness on the fatigue failure of the TBC was also discussed. |