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Pressureless fabrication of dense monolithic SiC ceramics from a polycarbosilane

Kaur, Sarabjeet and Riedel, Ralf and Ionescu, Emanuel (2014):
Pressureless fabrication of dense monolithic SiC ceramics from a polycarbosilane.
In: Journal of the European Ceramic Society, 34 (15), Elsevier Science Publishing, pp. 3571-3578, ISSN 09552219,
[Online-Edition: http://dx.doi.org/10.1016/j.jeurceramsoc.2014.05.002],
[Article]

Abstract

This paper presents the pressureless preparation of dense and crack-free near stoichiometric SiC monoliths via cross-linking and pyrolysis of a polycarbosilane, followed by polymer-infiltration-pyrolysis cycles. The composition and the porosity of the samples strongly depend on the processing temperature. Thus, at 1050–1100 °C, the SiC monoliths are X-ray amorphous and exhibit low amounts of oxygen and excess carbon; their porosity was rather high (>10%). Higher processing temperatures induced the crystallization of β-SiC. The removal of oxygen and excess carbon due to CO release allowed for obtaining near-stoichiometric compositions at 1700 °C. However, the residual porosity of the samples increased. The use of the PIP technique led already after six cycles to dense monoliths (residual porosity ca. 0.5%). The present study emphasizes the potential of the polymer processing technique for the fabrication of near stoichiometric and dense SiC monoliths, which might be used for structural applications in harsh conditions.

Item Type: Article
Erschienen: 2014
Creators: Kaur, Sarabjeet and Riedel, Ralf and Ionescu, Emanuel
Title: Pressureless fabrication of dense monolithic SiC ceramics from a polycarbosilane
Language: English
Abstract:

This paper presents the pressureless preparation of dense and crack-free near stoichiometric SiC monoliths via cross-linking and pyrolysis of a polycarbosilane, followed by polymer-infiltration-pyrolysis cycles. The composition and the porosity of the samples strongly depend on the processing temperature. Thus, at 1050–1100 °C, the SiC monoliths are X-ray amorphous and exhibit low amounts of oxygen and excess carbon; their porosity was rather high (>10%). Higher processing temperatures induced the crystallization of β-SiC. The removal of oxygen and excess carbon due to CO release allowed for obtaining near-stoichiometric compositions at 1700 °C. However, the residual porosity of the samples increased. The use of the PIP technique led already after six cycles to dense monoliths (residual porosity ca. 0.5%). The present study emphasizes the potential of the polymer processing technique for the fabrication of near stoichiometric and dense SiC monoliths, which might be used for structural applications in harsh conditions.

Journal or Publication Title: Journal of the European Ceramic Society
Volume: 34
Number: 15
Publisher: Elsevier Science Publishing
Uncontrolled Keywords: Polycarbosilane, SiC monoliths, Polymer derived ceramics (PDCs), Pressureless processing, Polymer infiltration pyrolysis (PIP)
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
Date Deposited: 07 Jul 2014 12:12
Official URL: http://dx.doi.org/10.1016/j.jeurceramsoc.2014.05.002
Identification Number: doi:10.1016/j.jeurceramsoc.2014.05.002
Funders: This work was financially supported by Xycarb Ceramic B. V. (Schunk GmbH).
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