Investigation of infrared spectral emissivity of low emittance functional coating artefacts

Abstract Accurate infrared spectral emissivity measurements play a vital role in many thermal and optical applications of high value industries. In this paper, we report the experimental investigation of the infrared spectral emissivity of low emittance functional coating artefacts. The functional coating uses 35 % aluminum particles as filler to reduce the surface emissivity. Fourier transform infrared spectrometer based infrared emissivity measurement systems, developed by NIM, were used in this investigation. The normal spectral emissivity of the coating was investigated both at NIM and BIAM in the spectral infrared range 3 μm –14 μm, and the temperature range 300 oC – 600 oC. The artefacts’ stability and the infrared emittance scale comparison between BIAM and NIM are reported in this paper. An indirect comparison between NIM and CCT was also carried out using the CVD-SiC sample that was used to validate the uncertainty claimed by NIM. The infrared emittance scales’ comparison results demonstrate the scales are clearly in agreement well within the overall comparison uncertainty.