Normal spectral emissivity measurement of graphite in the temperature range between 200°C and 500°C

•A normal spectral emissivity measurement system based on the Fourier transform infrared spectrometer is developed.•Measurement of the normal spectral emissivity within 3 μm to 5 μm of the graphite in the temperature range between 200 °C and 500 °C is performed.•Nonlinear models are proposed to build the dependences of the emissivity on the wavelength and the temperature.