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Pressureless synthesis of fully dense and crack-free SiOC bulk ceramics via photo-crosslinking and pyrolysis of a polysiloxane

Martínez-Crespiera, Sandra and Ionescu, Emanuel and Kleebe, Hans-Joachim and Riedel, Ralf (2011):
Pressureless synthesis of fully dense and crack-free SiOC bulk ceramics via photo-crosslinking and pyrolysis of a polysiloxane.
In: Journal of the European Ceramic Society, pp. 913-919, 31, (5), ISSN 09552219,
[Online-Edition: http://dx.doi.org/10.1016/j.jeurceramsoc.2010.11.019],
[Article]

Abstract

This paper presents the pressureless preparation of fully dense and crack-free SiOC ceramics via direct photo-crosslinking and pyrolysis of a polysiloxane. Elemental analysis revealed the presence of high levels of carbon in the SiOC ceramics. Thus, the samples showed the highest content (78–86 mol%) of segregated “free” carbon reported so far. XRD investigations indicated that the materials prepared at 1100 °C were X-ray amorphous, whereas the sample prepared at 1400 °C contained a turbostratic graphite-like phase and silicon carbide as crystalline phases, as additionally confirmed by TEM and Raman spectroscopy. Vickers hardness was measured to be 5.5–8.6 GPa. The dc resistivity of the prepared material at 1100 °C was 0.35 Ω m, whereas the ceramic pyrolyzed at 1400 °C showed a value of 0.14 Ω m; both values are much lower than those of other known SiOC materials. This latter feature was attributed to the presence of a percolating carbon network in the ceramic.

Item Type: Article
Erschienen: 2011
Creators: Martínez-Crespiera, Sandra and Ionescu, Emanuel and Kleebe, Hans-Joachim and Riedel, Ralf
Title: Pressureless synthesis of fully dense and crack-free SiOC bulk ceramics via photo-crosslinking and pyrolysis of a polysiloxane
Language: English
Abstract:

This paper presents the pressureless preparation of fully dense and crack-free SiOC ceramics via direct photo-crosslinking and pyrolysis of a polysiloxane. Elemental analysis revealed the presence of high levels of carbon in the SiOC ceramics. Thus, the samples showed the highest content (78–86 mol%) of segregated “free” carbon reported so far. XRD investigations indicated that the materials prepared at 1100 °C were X-ray amorphous, whereas the sample prepared at 1400 °C contained a turbostratic graphite-like phase and silicon carbide as crystalline phases, as additionally confirmed by TEM and Raman spectroscopy. Vickers hardness was measured to be 5.5–8.6 GPa. The dc resistivity of the prepared material at 1100 °C was 0.35 Ω m, whereas the ceramic pyrolyzed at 1400 °C showed a value of 0.14 Ω m; both values are much lower than those of other known SiOC materials. This latter feature was attributed to the presence of a percolating carbon network in the ceramic.

Journal or Publication Title: Journal of the European Ceramic Society
Volume: 31
Number: 5
Uncontrolled Keywords: Carbon, Electrical conductivity, Glass ceramics, Polymer derived ceramics (PDCs)
Divisions: 11 Department of Materials and Earth Sciences > Earth Science > Geo-Material-Science
11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
11 Department of Materials and Earth Sciences > Earth Science
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 04 Apr 2012 11:07
Official URL: http://dx.doi.org/10.1016/j.jeurceramsoc.2010.11.019
Identification Number: doi:10.1016/j.jeurceramsoc.2010.11.019
Funders: European Community FP6 (MCRTN-019601, PolyCerNet), Federal Ministry of Education and Research (BMBF, Berlin, Germany-project INFUNK)
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