Normal spectral emissivity measurement study of high-temperature alloy (316L) at 673–1273 K with a thermal oxidation surface

Abstract

One effective approach to better understanding the performance characteristics of high-temperature alloys is to study their thermal oxidation behavior, and to accurately determine their spectral emissivity is helpful for increasing the accuracy of temperature measurements. Using a self-developed high-temperature emissivity testing system, the normal spectral emissivity across the range 673–1273 K and a spectral band of 1–14 μm was measured relative to this background radiation. The normal spectral emissivity of 316L high-temperature alloy was investigated during the thermal oxidation process. The change in emissivity of 316L high-temperature alloy during thermal oxidation was observed. The emissivity of the 316L high-temperature alloy undergoes great changes during thermal oxidation; for example, at 1273 K it was 0.055 in its un-oxidized state but after 50 h’ thermal oxidation went up to 0.829. Below 1073 K the emissivity of 316L high-temperature alloy in 8–14 μm range showed little change, making it ideal for radiation thermometry. By fitting the measurement data, we derived that the emissivity of 316L high-temperature alloy has an exponential relationship with thermal oxidation temperature, and is a power function relationship with thermal oxidation time.