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C. Eisenmenger-Sittner, A. Eder, G. Schmid:
"Deposition, Characterization And Applications Of Thin Films On Granular Substrates";
Vortrag: 9th Symposium on Vacuum based Science and Technology, Kolobrzeg, Polen; 16.11.2015 - 19.11.2015.

In this work physical vapor deposition (PVD) techniques for the manipulation of the surfaces of granular materials are discussed. Several challenges have to be addressed for this purpose:
Extensive intermixing of relatively large amounts of powders, granulates or fibres under vacuum conditions is mandatory for uniform coating due to the line of sight process of PVD processes. This is not trivial due to agglomeration effects and different trickling behaviour of granular matter in vacuum as compared to ambient atmosphere. An intermixing device based on rotation and concussion of a specially shaped powder container is presented. Up to one litre of granulate can be coated with high uniformity using this set-up.
Also the determination of the thickness of coatings on granulates is an involved task. We present an optical method based on advanced image processing techniques to determine the thickness of transparent coatings on small transparent particles. This method is used to characterize the above mentioned process in respect to thickness uniformity and thickness distribution on statistically significant amounts of particles and to compare measured thicknesses to those predicted by a theoretical model.
Finally, possible applications of coated granulates are presented. The focus is laid on hollow glass microspheres coated by a catalytic material for the controlled storage and release of hydrogen. This concept may yield high storage efficiency for hydrogen combined with low total weight and safe handling. Also other applications like coating sintering powders by diffusion barriers or fundamental aspects of measuring the conductivity of metal coated insulating particles will be discussed.
From these examples future prospects of coated granulates in several technological fields will be highlighted and innovative concepts for new functional materials will be presented.

This work is supported by the Austrian Science Fund, Projects, P-22718 and TRP-281