Изменение нормальной спектральной излучательной способности при плавлении элементов

An experimental and computational study of the normal spectral emissivity during melting of various metals was carried out, the installation scheme and the method of conducting experiments were given. The possibilities of the electromagnetic theory for describing the dependence of the behavior of the normal spectral emissivity of metals and semimetals are evaluated.

Investigation of High-Temperature Normal Infrared Spectral Emissivity of ZrO2 Thermal Barrier Coating Artefacts by the Modified Integrated Blackbody Method

Zirconium oxide (ZrO2) is widely used as the thermal barrier coating in turbines and engines. Accurate emissivity measurement of ZrO2 coating at high temperatures, especially above 1000 °C, plays a vital role in thermal modelling and radiation thermometry. However, it is an extremely challenging enterprise, and very few high temperature emissivity results with rigorously estimated uncertainties have been published to date. The key issue for accurately measuring the high temperature emissivity is maintaining a hot surface without reflection from the hot environment, and avoiding passive or active oxidation of material, which will modify the emissivity. In this paper, a novel modified integrated blackbody method is reported to measure the high temperature normal spectral emissivity of ZrO2 coating in the temperature range 1000 °C to 1200 °C and spectral range 8 μm to 14 μm. The results and the associated uncertainty of the measurement were estimated and a relative standard uncertainty better than 7% (k = 2) is achieved.

Re-investigation of the Normal Spectral Emissivity at 684.5 nm of Solid and Liquid Molybdenum

In this work, we present normal spectral emissivity data of solid and liquid molybdenum at a wavelength of 684.5 nm. The presented results are novel measurements on molybdenum, a material, which was already measured 15 years ago by our group. The present results indicate a lower emissivity in the liquid phase. The novel measurements were done within the European Metrology Programme for Innovation and Research (EMPIR) project 17IND11 Hi-TRACE. The optimized measuring system is an ohmic pulse-heating apparatus combined with microsecond Division of Amplitude polarimetry.

Normal spectral emissivity of liquid Al-Ti binary alloys

The normal spectral emissivity ε of four compositions in the Al-Ti binary liquid system was measured in dependence of the wavelength and temperature. It was found that all compositions show negligible temperature dependence. At a wavelength of 940 nm, the emissivity amounts to 0.37, 0.40, 0.32, and 0.31 for Ti, Al20Ti80, Al50Ti50, and Al70Ti30, respectively. The dependence of the emissivity on composition is in good agreement with literature data of binary and multi-component Al-Ti-based alloys. Using the classical Drude model, electrical resistivities are predicted for the Al-Ti system from the measured emissivities. Comparison with existing data from literature for Al show reasonable agreement.