Design and Evaluation of Zirconia Based Thermal Barrier Powders for Advanced Engines


Advanced utility, diesel and turbines engines used widely in aerospace, chemical and oil industries are based on plasma sprayed thermal barrier coatings. The successful performance of these coatings during servicing are relied mostly on the careful design, selection and analysis of zirconia-based ceramic powders stabilized with yttria and ceria. Different design of sampling techniques relevant for each evaluates property is a key factor to obtain reliable data. Significant property differences were observed for single and mixed powders. In the present work the particle size, its distribution, apparent density, flow rate, biased standard deviation, unbiased standard deviation and phases were characterized using sieving, flowmeter, scanning electron microscopy (SEM), X-ray diffraction (XRD), step scanning X-ray diffraction, energy dispersive spectroscopy (EDS), electron microprobe analysis (EPMA) and FT-IR. Two single alloyed zirconia powders of zirconia- 25 wt% CeO2-2.5 wt% Y2O3 (Sulzer Metco 205NS) and zirconia- 8 wt% Y2O3 (Sulzer Metco 204NS-G) and mixture of these powders 80 wt% (Sulzer Metco 205NS) and 20 wt% (Sulzer Metco 204NS-G) were investigated. The particle shape has a remarkable effect on the flow rate and apparent density rather than the other properties. The particle distribution gives important noticeable information for the plasma spraying coatings.