He Shufang, Li Shuai, Dai Caihong, Liu Jinyuan, Wang Yanfei, Sun Ruoduan, Feng Guojin, Wang Jinghui
Division of Optical Metrology, National Institute of Metrology, Beijing 100029, China.
Academy of Artificial Intelligence, Beijing Institute of Petrochemical Technology, Beijing 102627, China.
Materials (Basel). 2025 Jul 19;18(14):3392. doi: 10.3390/ma18143392.
Measuring the emissivity of an infrared radiant sample with high accuracy is important. Previous studies reported on the multi- or two-temperature calibration methods, which used a reference blackbody (or blackbodies) to eliminate the background radiation, and assumed that the background radiation was independent of temperature. However, in practical measurements, this assumption does not hold. To solve the above problems, this study proposes a modified two-temperature calibration method and facility. The two temperature points are set in a certain small interval based on the proposed calculation method; based on the indication of the approximation that the emissivities of the sample and the background radiations remain the same at these two temperatures, the emissivities can be calculated with measurement signals at these two temperatures, and a reference blackbody is not needed. An experimental facility was built up and three samples with emissivities around 0.100, 0.500, and 0.900 were measured in (8~14) μm. The relative expanded uncertainties were 9.6%, 4.0%, and 1.5% at 60 °C, respectively, and 8.8%, 5.8%, and 1.2% at 85 °C ( = 2), respectively. The experimental results showed consistency with the results obtained using other methods, indicating the effectiveness of the developed method. The developed method might be suitable for samples whose emissivities are temperature insensitive.
高精度测量红外辐射样品的发射率非常重要。先前的研究报道了多温度或双温度校准方法，这些方法使用一个（或多个）参考黑体来消除背景辐射，并假设背景辐射与温度无关。然而，在实际测量中，这一假设并不成立。为了解决上述问题，本研究提出了一种改进的双温度校准方法及装置。基于所提出的计算方法，在一定的小间隔内设置两个温度点；基于样品和背景辐射在这两个温度下发射率保持不变这一近似假设，利用这两个温度下的测量信号即可计算出发射率，无需参考黑体。搭建了实验装置，并对发射率约为0.100、0.500和0.900的三个样品在（8~14）μm波段进行了测量。在60℃时，相对扩展不确定度分别为9.6%、4.0%和1.5%；在85℃（ = 2）时，相对扩展不确定度分别为8.8%、5.8%和1.2%。实验结果与使用其他方法获得的结果一致，表明所开发方法的有效性。所开发的方法可能适用于发射率对温度不敏感的样品。
