Radiative properties characterization of ZrB₂-SiC-based ultrahigh temperature ceramic at high temperature

Experimental investigations of radiative property on pre-oxidized ZrB₂-SiC-15vol.%-C ultrahigh temperature ceramic (ZSC UHTC) at high temperature range of 1100-1800°C were performed. By Fourier transform infrared radiant (FT-IR) spectrometer, spectral emissivity was measured in the wavelength region between 3 and 18μm. Total normal emissivity was calculated using spectral emissivity data via theoretical formula. It has been found that high emissivity for all the testing specimens was presented, and the total normal emissivity is between 0.65 and 0.92 with temperature range from 1100 to 1800°C. Moreover, the total normal emissivity of pre-oxidized ZSC ceramic decreased non-monotonously as the temperature increased. The total normal emissivity decreased as the testing temperature increased from 1100 to 1800°C, whereas the total normal emissivity at the testing temperature of 1600°C was higher than that of 1400 and 1800°C. Macroscopical surface morphology and microstructure were carried out before and after the testing.