Dresden 2009 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 45: Phase Transitions III
MM 45.1: Talk
Thursday, March 26, 2009, 15:15–15:30, IFW B
Colloidal model systems for undercooled metallic melts — •Ina Klassen1, Patrick Wette1, Dirk Holland-Moritz1, Thomas Palberg2, Stephan V. Roth3, and Dieter M. Herlach1 — 1Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt, 51170 Köln, Germany — 2Institut für Physik, Johannes-Gutenberg-Universität Mainz, — 3HASYLAB, DESY, 22603 Hamburg, Germany
The knowledge of short-range order and nucleation behavior in a liquid is of fundamental importance for understanding the crystallization process of metals. To get a valuable insight in this process on the atomic length scale, we chose the way of analyzing a colloidal model system of charged silica spheres in aqueous solution. Its interaction can be controlled in a precise way by varying sodium hydroxide concentration. This colloidal system is characterized by convenient time scales between seconds and minutes and particle distances up to 500nm and is thus accessible by simple, yet powerful optical techniques. In addition to this, USAXS technique was used to determine the short-range order and nucleation behavior far from equilibrium state. These results are compared particularly with regard to those of a metallic system and show similarities which verify the chosen colloidal system as a good model system for metals.