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The spectral emissivity determination of thermal protection ceramic material with FT-IR spectrometer


Z. Wang1 and J. Dai1

1Harbin institute of technology, P.R. China

Keywords: FTIR
property: spectral emissivity
material: thermal protection ceramic

Spectral emissivity of materials is an important parameter of thermal radiation characterization[1]. This paper focuses on the thermal radiation characteristics of thermal protection materials. When high speed aircraft fly at ultra-high speed, the aircraft surface may reach above 2000℃ for aerodynamic heating. In order to reduce the surface temperature, the emissivity of TiO2 oxidation coating and ultra-high temperature thermal protection ceramic ZrB2-SiC have been researched. In fact, when aircraft fly in the atmospheric environment, the tip of aircraft may be heated over 2000 ℃. The high temperature affects the normal operation of aircraft interior equipment. While the emissivities of coatings are different, the thermal radiation power of surface is different. The heat balance temperature has been quantitatively analyzed in the aerodynamic heating mode with different surface emissivity. The emissivity of thermal protection materials surface greatly influences heat balance temperature.Thermal protection materials with high emissivity can reduce the thermal equilibrium temperature, so high emissivity thermal protection materials can effectively protect the aircraft interior device to work. On the other hand, the aircraft surface can withstand higher heat flow with high emissivity surface. The spectral emissivity measurement system has been established in Harbin institute of technology, China. The Fourier transform infrared (FTIR) spectrometer is calibrated using multi-point temperature calibration method[2,3]. The temperature range is from 100 and to 2400 ℃. The spectrum covers the range from 3 to 20μm. The emissivity of TiO2 coatings and ultra-high temperature ceramic ZrB2-SiC have been determined by the established eimissivity measurement system. The spectral emissivity of TiO2 coatings is about 0.9 at 700℃ in the wavelength range of 8 ~ 14 μm. The emissivity of ultra-high ceramic ZrB2-SiC has been determined at 1800℃[4,5]. The total emissivity of ZrB2-SiC is 0.73. Spectral linearity of spectral emissivity measurement system is less than 1%, the uncertainty values of spectral emissivity measurement results are less than 3%.

References
  1. R. Savino, M. De Stefano Fumo, D. Paterna et al. Aerosp. Sci. Technol. A9,2(2005)

  2. C. Monte, B. Gutschwager, S.P. Morozova. Int. J. Thermophys. A30,1(2009)

  3. HUANG Ye, FANG Yong-Hua, XUN Yu-Long et al. J.Infrared Millim.Waves.A23,2(2004)

  4. G. Neuer and G. Jaroma-Weiland Int. J. Thermophys.A19,3(1998)

  5. Songhe Meng, Hongbo Chen, Jianghua Hu et al. Material & Design.A32(2011)

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