An emissivity measurement apparatus for near infrared spectrum

• A new emissivity measurement apparatus for near infrared spectrum is reported.
• We present an improved method to minimize the measurement error.
• The spectral emissivities of TA1, oxidized nickel and 304 austenitic stainless steel are measured and discussed.
• The uncertainty of the apparatus is discussed and calculated in detailed.

This study develops a new experimental apparatus for infrared spectral emissivity measurements which consists mainly of the following four parts: sample heating system, blackbody furnace, optical system, and data acquisition system. This apparatus focuses on the near-infrared spectral emissivity measurement covering the temperature range from 473 K to 1273 K and the wavelengths between 0.8 μm and 2.2 μm. The apparatus and the measurement method are described in detail, and an improved method is presented to minimize measurement error. The spectral emissivity of pure titanium TA1, oxidized nickel and 304 austenitic stainless steel are measured to validate the reliability and reproducibility of experimental apparatus. The experimental results in this study are in good agreement with those of other literatures. Various uncertainty sources in emissivity measurement are analyzed, and the combined standard uncertainty of this system is less than 3.9%.