ZrO2 and Y2O3-stablized ZrO2 (YSZ) coatings were deposited on NiCoCrAlY coated superalloys using an arc ion plating system. The crystalline structure, chemical composition, and morphology of the coatings were systematically investigated using X-ray diffraction, X-ray photoelectron spectroscopy, as well as scanning electron microscopy. The thermal stability of YSZ coatings were investigated by oxidation and thermal shock tests. The results showed that near-stoichiometric ZrO2 coatings can be obtained at a relatively large range of O2 flow rates (134-400 sccm), with the main phase of monolithic zirconia being identified. YSZ coatings exhibited excellent thermal stability in the oxidation and thermal shock tests. Before and after thermal tests, only the tetragonal zirconia (t-ZrO2) phase was identified in the YSZ coatings.
Keywords: ZrO2 coating, Arc ion plating, Phase structure,; Thermal stability, Thermal shock resistance.