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

Nitrides of Non‐Main Group Elements

Abstract In the last two decades, there has been a renewed interest in the chemistry of nitrides and nitridometalates. Both binary and higher nitrides MxNy have already featured prominently as refractory materials, corrosion‐ and mechanical wear‐resistant coatings, hard materials, and hard magnets; thin films are used as diffusion barriers in integrated circuits. Whereas research on binary transition metal nitrides is mostly driven by technical and economic interests, the investigation on nitridometalates primarily focuses on exploration with respect to the development of new synthetic strategies and the design of new materials. Within this field of interest, especially the nitride chemistry of rare earth metals is still comparably undeveloped. Chemical bonding in binary nitrides varies from primarily salt‐like via covalent to metallic, whereas nitridometalates are best described as containing covalent complex anions [MxNy]z− with alkali, alkaline earth, or rare earth metal cations providing electroneutrality