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C. Eisenmenger-Sittner:
"Thin Film Deposition on Uncommon Substrates: Deposition and Possible Application of PVD Coatings on Granulates";
Hauptvortrag: 6th Vacuum and Surface Sciences Conference of Asia and Australia (VASSCAA-6), Pak-China Friendship Center, Islamabad/Pakistan (eingeladen); 09.10.2012 - 13.10.2012.

When thinking of thin film deposition, often large surfaces like architectural glass panes or high quality optical and optoelectronic components come to mind. Also deliberately patterned surfaces as they are common for microelectronics are a classical field for manufacturing small components by thin film techniques.
The properties of modern materials, on the other hand, are determined by the presence of internal interfaces to a high degree. In addition, they are often manufactured by the compaction of powders or granulates, so that thin film deposition techniques may serve as a means of functionalizing their surfaces to influence the compaction behaviour and to tune the final material properties.
In the first part or this work the possibilities to apply 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:
(i) Extensive intermixing of powders, granulates or fibers under vacuum conditions is mandatory fur uniform coating due to the line of sight process of PVD processes. This is often not trivial due to agglomeration effects and deviations of the trickling behaviour of granular matter as compared to trickling on ambient atmosphere. Optimum intermixing geometries and set-ups are discussed.
(ii) The determination of the thickness of coatings on granulates is an involved task. We present optical methods based on advanced image processing techniques to facilitate this demand for transparent coatings on transparent granulates as e. g. small synthetic diamonds or hollow glass microspheres.
The second part of the presentation deals with possible applications of coated granulates. Examples for these applications are
(i) High performance heat sink materials based on the system copper-diamond with tuneable coefficients of thermal expansion. These materials are an excellent example for the collective influence of modified interfaces on the thermo mechanical properties of the resulting materials.
(ii) 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.
Starting from these examples the future prospects of coating 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-19379, P-22718 and TRP-6