Dresden 2003 – wissenschaftliches Programm

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M: Metallphysik

M 17: Hauptvortrag Wunderlich

M 17.1: Hauptvortrag

Dienstag, 25. März 2003, 14:00–14:30, IFW A

Interfaces and Nano-crystallites for Advanced Materials — •Wilfried Wunderlich — Nagoya Institute of Technology, 466-8555 Nagoya, Japan

The understanding of interface properties on atomic scale is the key for developing advanced composite-materials. HRTEM-micrographs and MD-simulations of five different examples show the principles of atomic bonding at interfaces and surfaces of nano-crystallites.

1) After quenching an annealed Al-Li alloy a super-saturation remains in the matrix, which leads to the formation of nano-sized precipitates after a sufficient long diffusion time even at room temperature.

2) Metallic nano-particles are embedded in graphite-nano-fibers (GNF) when growing by plasma-enhanced chemical vapor deposition (PECVD) on Palladium-surfaces. If the particles contain Hydrogen, their lattice is changed.

3) During the Sol-Gel-process precursor materials in the aqueous slurry are transformed into nano-sized ceramic crystallites, in which three different nano-size effects can be distinguished, structural surface relaxations, changed orbital-band energies and reduced polarization ability.

4) When an organic Eosin molecule is bonded on a ZnO surface, the number of covalent bonds has a strong influence on the electronic band structure. This interface optimization can increase the efficiency of solar cells.

5) Studies of the grain boundary mobility in Gold by an in-situ HRTEM experiment lead to the characterization into four different grain boundary types.