Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 23: Topical Session Bulk Nanostrucured Materials V - Microstructure and Characterization III
MM 23.2: Vortrag
Dienstag, 27. März 2012, 11:45–12:00, H 0107
Nano crystallization in glasses, their structure and chemistry as analyzed by anomalous small angle X-ray scattering — •Vikram Singh Raghuwanshi1, Armin Hoell1, Ruzha Harizanova2, and Christian Rüssel3 — 1Helmholtz Zentrum Berlin für Materialian und Energie, Berlin, Germany — 2University of Chemical Technology and Mateallurgy,Sofia,Bulgaria. — 3Otto-Schott-Institut,Jena, Germany
Silicate glasses containing nano crystals have valuable applications in various fields. The aim is to estimate the structural parameter and composition of the nanostructure embedded in silicate glass system by SAXS and ASAXS. We have chosen two silicate systems. Firstly, glass ceramics having composition 62.9SiO2/13.6Na2O/8.5MnO/15.0Fe2O4-x (mol %) and by applying time/temperature heat treatment regime, nano-sized crystalline phase of MnxFe1-xFe2O4 is precipitated. ASAXS measurements were performed near the Fe and Mn K edge. Secondly, glass ceramics having composition 69.6SiO2/7.5Al2O3/15.0K2O/1.9Na2O/4BaF2/2BaO (mol %) shows precipitation of BaF2 nanocrystals during controlled annealing at different time/temperature scales. ASAXS measurements were performed near the Ba L3 edge. Fitting of ASAXS curve shows the formation of spherical particles surrounded with Si enriched lower electron density layer. This layer acts as a diffusion barrier and due to which, further growth of the nanoparticles is kinetically constraint. Also quantitative information and composition of the particles is evaluated.