HIGH-TEMPERATURE STABILITY OF CEO2-Y2O3 STABILIZED ZIRCONIA PLASMA SPRAY POWDER - XPS, STEM, AND DTA INVESTIGATIONS

Advanced investigations on high temperature stability of commercial prealloyed ceria-yttria-zirconia powder, suitable for the manufacturing of Thermal Barrier Coatings (TBC), have been carried out by means of X-ray Photoelectron Spectroscopy (XPS), Scanning Transmission Electron Microscopy (STEM), Differential Thermal Analysis (DTA), and Thermogravimetry (TGA) with a view to foresee their behaviour in the plasma jet atmosphere and oxidizing service environment. Thermal treatments of the powder were performed in a thermobalance in both oxidizing (static air) and reducing (flowing N2/H2 = 10%) atmospheres up to 1873 K and then cooled down. Under static air conditions, two exothermal reactions taking place at 700 and 1300 K were disclosed by DTA experiments.