Infrared radiative properties of plasma-sprayed strontium zirconate

The room temperature directional-hemispherical reflectance and transmittance spectra of free-standing atmospheric plasma sprayed SrZrO3 coatings with different thicknesses were measured in the wavelength range of 0.8-6.0 µm, and the absorption coefficient and scattering coefficient as a function of wavelength were extracted and compared with conventional yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs). Results showed that SrZrO3 is a high scattering, low absorption, and semitransparent material in the wavelength range where turbine engine thermal radiation is most concentrated. The absorption coefficient is extremely low and the scattering coefficient decreases with the increase of wavelength, which is caused by the decrease of the relative size of the scattering center compared with the wavelength. In the measured wavelength range, the scattering coefficient of SrZrO3 is higher than that of YSZ, which is beneficial for the TBC applications.