Fig. 1. Schematic of the integrated blackbody principle (a) A integrated blackbody formed by a sample on the cavity bottom coupled with the cavity wall, (b) a sample moved from the bottom to the mouth of the cavity

Fig. 2. Distributions of the radiance temperature of the integrated blackbody cavity at a nominal temperature of 1 000 ℃

Fig. 3. Simulation and validation results of the effective emissivity of the integrated blackbody

Fig. 4. Schematic of the emissivity measurement device using the integrated blackbody principle

Fig. 5. The spectral outputs of the integrated blackbody and the graphite material (a) The spectral outputs during the spectral emissivity measurement of a graphite material at a nominal temperature of 1 000 ℃ of the integrated blackbody, (b) The effective spectral outputs of the integrated blackbody and the graphite material in the measurement state at the nominal temperatures of 1 000 ℃, 1 300℃ and 1 500 ℃

Fig. 6. The measurement and comparison results of the infrared spectral emissivity of graphite

Fig. 7. Heat transfer model of a sample surface

Fig. 8. The maximum temperature drop evaluations of a graphite material

Fig. 9. Results of the SSE measurements

Fig. 10. Results of the linearity of the spectral responsivity

Fig. 11. Linearity correction coefficients of the spectral responsivity

Table 1. Uncertainties and evaluation methods of the materials infrared spectral emissivity measurements using integrated blackbody principle

Table 2. Summary of measurement uncertainties of the infrared spectral emissivity of the graphite material