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Meitingen, Germany

Lehmann T.,University of Stuttgart | Baier J.,University of Stuttgart | Leineweber A.,Max Planck Institute for Intelligent Systems (Stuttgart) | Leineweber A.,TU Bergakademie Freiberg | And 2 more authors.
Advanced Engineering Materials

Silicon Carbide (SiC) samples with controlled carbon contents are manufactured from polymeric precursors. Based on X-ray diffraction (XRD) data, a correlation of the excess carbon content and the crystallization kinetics of silicon carbide are determined for the obtained pyrolysates. The crystallization mechanisms as well as the corresponding activation energies EA are also determined. Furthermore, the influence of the carbon content on the oxidation behavior of these pyrolysates is studied. A model for the oxidation of the prepared silicon carbide-based materials is proposed. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Bryant B.,SGL Group | Wyatt A.,SGL Group | Fuchs H.,SGL Carbon GmbH
Stahl und Eisen

SGL Pro Arc is an innovative tool for modelling and optimizing the EAF regulation and power system. It has been applied to EAFs globally to improve performance, solve maintenance issues and provide facts for investment decisions. It models the three-phase EAF power system from the transmission system through the arcs. It graphically documents the EAF operating points in terms of a feasible operating region and emulates the response of the EAF regulation and mast hydraulics to disturbances such as scrap cave-ins, melting of heavy or light scrap, or poor slag foaming conditions. Source

Hietel D.,Fraunhofer Institute for Industrial Mathematics | Noth A.,Fraunhofer Institute for Silicate Research | Rothmann M.,SGL Carbon GmbH
Chemical Fibers International

Ceramic fibers for high-tech applications require intensive developments concerning precursor synthesis and fiber spinning. The spinning process starts at laboratory scale with only few filaments and needs to be upscaled to pilot plant and industrial scale with hundreds or even thousands of filaments. Due to the significant interaction of filaments and surrounding inert atmosphere, the behavior in the spinning tower completely changes with higher numbers of filaments. How these effects are incorporated in a model of the gas flow including its influence by the filament spinning will be described. In 2 examples for melt- and dry-spinning of ceramic fibers it will be demonstrated how characteristic properties derived from experiments on a laboratory scale can be efficiently transferred to a pilot plant scale by use of simulations. For both applications the spinning tower was built according to the conditions derived from the simulation results, and experimentally proven to work. Source

Lis T.,AGH University of Science and Technology | Korzec N.,AGH University of Science and Technology | Frohs W.,SGL Carbon GmbH | Tomala J.,SGL Carbon Polska S.A. | And 2 more authors.
Journal of Wood Chemistry and Technology

In addition to the many benefits of coal tar pitch, these materials are known to contain polycyclic aromatic hydrocarbons. For this reason, studies are being developed to elaborate new, ecologically friendly, alternative binders for carbon–graphite technology. This article presents the results of wood tar recovered during thermal degradation of selected types of woods as alternative binders in the manufacture of carbon materials. Two kinds of wood tars obtained from different raw materials were analyzed. Sawdust thermal conversion makes it possible to obtain carbon binders with a lower coking value and quinoline-insoluble matters in comparison to coal tar pitch. These binders produce significantly reduced emissions of polycyclic aromatic hydrocarbons in carbon–graphite technology. Carbon samples manufactured using wood-derived binders with carbon fillers showed similar density and mechanical compression strength values compared to those based on conventional coal tar pitch binders. 2016 Copyright © Taylor & Francis Group, LLC Source

Schweiss R.,SGL Carbon GmbH | Steeb M.,SGL Carbon GmbH | Wilde P.M.,SGL Carbon GmbH | Schubert T.,FutureCarbon GmbH
Journal of Power Sources

Microporous layers (MPLs) of gas diffusion layers (GDLs) were modified by multiwall carbon nanotubes (MWCNTs) using a wet-chemical approach. Carbon nanotubes were dispersed along with other MPL components and coated onto a GDL backing. The electronic resistance of the GDL was significantly reduced by the addition of MWCNTs. A larger mean pore diameter was obtained as compared to the reference substrates. The improved performance of proton exchange membrane fuel cells (PEMFCs) using such CNT-doped GDLs is attributed to a lower electronic resistance along with improved mass transport. Synergy effects of different carbon materials with MWCNTs and advanced dispersion processes were found to play a key role in achieving the performance improvements. © 2012 Elsevier B.V. All rights reserved. Source

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