Isothermal Oxidation and Spectral Response Characteristics of 8YSZ/Y3Al5O12:Ce3＋Photosensitive Composite Thermal Barrier Coating

Abstract

In order to monitor the residual thermal stress in the ceramic layer of thermal barrier coating during the oxidation process，8YSZ/Y3Al5O12:Ce3＋photosensitive composite thermal barrier coatings with different Y3Al5O12:Ce3＋content were prepared.The failure mechanism of the isothermal oxidation process of 8YSZ/Y3Al5O12:Ce3＋photosensitive composite thermal barrier coatings with different Y3Al5O12:Ce3＋content was studied，and the intrinsic response mechanism between the residual thermal stress inside the ceramic layer and the peak wavelength of the emission spectrum of Y3Al5O12:Ce3＋was elaborated.In addition，the relationship between peak wavelength offset of the emission spectrum of ceramic layer of 8YSZ/Y3 Al5 O12:Ce3＋photosensitive composite thermal barrier coating and oxidation time was studied，and the sensing equation of isothermal oxidation time and spectral change of 8YSZ/10%Y3 Al5 O12:Ce3＋photosensitive composite thermal barrier coating was fitted.Results showed that the failure of the 8YSZ/Y3Al5O12:Ce3＋photosensitive composite thermal barrier coating during the 100 h isothermal oxidation at 1 050 ℃was mainly caused by the residual thermal stress in the ceramic layer，and with the increase of oxidation time，the residual thermal stress inside the ceramic layer increased，and the peak wavelength of the emission spectrum of Y3Al5O12:Ce3＋was offset to the shortwave direction.Furthermore，the sensing equation of 8YSZ/10%Y3Al5O12:Ce3＋photosensitive composite thermal barrier coating emission peak wavelength offset and oxidation time was Δλ ＝155.785 07·t0.00415-154.792 58.Therefore，the residual thermal stress in the ceramic layer during the oxidation process could be characterized by the migration rule of the peak wavelength of the emission spectrum.

Keywords

•  thermal barrier coating|y3al5o12:ce3＋|isothermal oxidation|residual thermal stress