Dresden 2009 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 23: Topical Session Heterogeneous Nucleation and Initial Evolution of Microstructure - Poster
MM 23.6: Poster
Dienstag, 24. März 2009, 14:45–16:30, P4
Binary Mixtures of Charged Colloidal Suspensions and their Role as Model Systems — •Nina J. Lorenz1, Patrick Wette2, Thomas Palberg1, Hans Joachim Schoepe1, and Tsuneo Okubo3 — 1Institute of Physics, University Mainz, Germany — 2Institute for Raumsimulation DLR Cologne, Germany — 3Cooperative Research Centre, Yamagata University, Yonezawa, Japan,
We investigate colloidal charged sphere mixtures in aqueous dispersion, exploring their possible use as conveniently accessible models for metallic binary mixtures. Using static and dynamic light scattering, torsional resonance spectroscopy and optical microscopy we investigate the structure, elasticity and solidification kinetics of mixtures with different size- and charge ratio. We find a rich variety of binary phase diagrams similar to those in metal systems including spindle, azeotropic and eutectic types [1, 2]. Eutectic-like behaviour is found for large asymmetries in the mixtures and demixing confirmed by diffusion experiments. The independent solidification of the segregating components is monitored with time resolved elasticity measurements. In addition we find interesting morphologies not unlike those in metal eutectics, but still considerably altered due to the different system dynamics. [1] T. Palberg, N. Lorenz, H.J. Schoepe, P. Wette, I. Klassen, D. Holland-Moritz, D.M. Herlach, in D. Herlach et. al.: Solidification in multicomponent melts, VCH-Wiley Weinheim, 2008, pp. 185-212, Solidification experiments in single component and binary colloidal melts [2] N. Lorenz, J.Liu, T. Palberg: Phase behaviour of binary mixtures of colloidal charged spheres, Colloids Surf. A 319, 109 (2008)