The main topic of project C2 is the modelling and characterization of the reflection of electromagnetic radiation at multiscaled porous structures subjected to high temperatures. In one part of the project this topic is pursued by the investigation of the broadband reflection of thermal radiation in the near- and far-infrared in view of the realization of novel thermal barrier coatings for aircraft and gas turbine blades. In the other part of the project we investigate the selective reflection of visible light by structural effects towards high temperature stable colors for ceramic glazes which do not require toxic components.
A photonic glass, a disordered arrangement of monodisperse spheres, is the main building block of the envisaged optical materials. The nano and micro spheres produced in C6 are deposited in a dense disordered arrangement in C4. A photonic glass layer from 3 µm particles allows broad band reflection of thermal radiation at 1500 K. Reduction of particles to nano dimensions leads to selective and angle independent reflection of visible light.
Fig. 1: Reflectivity of the 100 µm thick photonic glass coating made of 3.3 µm yttria doped ZrO2 microparticles after annealing in air. The inset shows the SEM of the coating. The two peaks originate from moisture and CO2-absorption and do not compromise the function.
|Prof. Dr. rer. nat. Manfred Eich, |
|Dr. rer. nat. Alexander Petrov,|
thermal barrier coatings
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