A pure tetragonal europium-doped yttrium-stabilized zirconia thermal barrier coating: Phase structure and luminescence

YSZ:Eu powder was prepared by sol spray pyrolysis method. Thermal barrier coatings (TBCs) composed of Eu³⁺-doped pure tetragonal yttrium-stabilized zirconia (namely, YSZ:Eu) were fabricated by air-plasma spraying technique. Crystal structure and fluorescence intensity of YSZ:Eu coating were investigated after aging at 1200 °C for 5 − 100 h. X-ray diffraction (XRD) indicates that tetragonal phase in YSZ:Eu coating had high resistance to degradation over a wide range of time periods and temperatures. Luminescence results indicate that asymmetry ratios of the fluorescence emission spectra were stable in a range of 1.2 ± 0.2. Relationships between phase structure and lattice distortion were further studied by fluorescence spectroscopy measurement using I₆₀₆/I₅₉₀ intensity ratio. The fluorescence results were consistent with those drawn by XRD, where the high stability of YSZ:Eu coating was confirmed. Excellent thermal stability, in terms of both the phase structure and luminescence intensity, of YSZ:Eu coating indicates that the present preparation method is suitable for phosphor powder applications.