A measurement apparatus based on the optical fiber spectrometer is established to measure the directional spectral emissivity in the near infrared band. The sample is heated by a self-designed silicon carbide heater. The measurement angle can be adjusted from 0° to 82° by rotating the fiber collimating lens installed in a motorized rotary stage. The radiation signals of the sample and blackbody can be detected with a micro-optical fiber spectrometer in real time. The spectral emissivities of silicon wafer, silicon carbide, molybdenum, and tungsten are measured to verify the reproducibility and reliability of the apparatus. Furthermore, the directional spectral emissivity of high-purity chromium is investigated in the wavelength range from 950 nm to 1600 nm and the temperature range from 823 K to 1073 K. The influences of wavelength, temperature, and measurement angle on the spectral emissivity are analyzed in detail. It is found that the directional spectral emissivity of chromium decreases with the increasing wavelength and the temperature. The spectral emissivity of chromium rises slowly and then falls sharply with the increasing measurement angle. The combined uncertainty of emissivity measurement is evaluated, which is no more than 3 % for the wavelength and temperature range considered.

建立了基于光纤光谱仪的测量装置，以测量近红外波段的定向光谱发射率。样品由自行设计的碳化硅加热器加热。通过旋转安装在电动旋转平台上的光纤准直透镜，可以将测量角度从0°调整到82°。样品和黑体的辐射信号可以用微光纤光谱仪实时检测。测量硅晶片，碳化硅，钼和钨的光谱发射率，以验证设备的再现性和可靠性。此外，研究了高纯度铬在950 nm至1600 nm波长范围和823 K至1073 K温度范围内的定向光谱发射率。波长，温度，详细分析了光谱发射率的测量角度。发现铬的定向光谱发射率随波长和温度的升高而降低。铬的光谱发射率随测量角度的增加而缓慢上升，然后急剧下降。评估了发射率测量的组合不确定度，对于所考虑的波长和温度范围，其不确定度不超过3％。