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Polymer-Derived Silicon Oxycarbide/Hafnia Ceramic Nanocomposites. Part II: Stability Toward Decomposition and Microstructure Evolution at T≫1000°C

Ionescu, Emanuel and Papendorf, Benjamin and Kleebe, Hans-Joachim and Riedel, Ralf (2010):
Polymer-Derived Silicon Oxycarbide/Hafnia Ceramic Nanocomposites. Part II: Stability Toward Decomposition and Microstructure Evolution at T≫1000°C.
In: Journal of the American Ceramic Society, 93 (6), Wiley, pp. 1783-1789, ISSN 00027820,
[Online-Edition: http://dx.doi.org/10.1111/j.1551-2916.2009.03527.x],
[Article]

Abstract

This study presents first investigations on the high-temperature stability and microstructure evolution of SiOC/HfO2 ceramic nanocomposites. Polymer-derived SiOC/HfO2 ceramic nanocomposites have been prepared via chemical modification of a commercially available polysilsesquioxane by hafnium tetra (n-butoxide). The modified polysilsesquioxane-based materials were cross-linked and subsequently pyrolyzed at 1100°C in argon atmosphere to obtain SiOC/HfO2 ceramic nanocomposites. Annealing experiments at temperatures between 1300° and 1600°C were performed and the annealed materials were investigated with respect to chemical composition and microstructure. The ceramic nanocomposites presented here were found to exhibit a remarkably improved thermal stability up to 1600°C in comparison with hafnia-free silicon oxycarbide. Chemical analysis, X-ray diffraction, FTIR, and Raman spectroscopy as well as electron microscopy (SEM, TEM) studies revealed that the excellent thermal stability of the SiOC/HfO2 nanocomposites is a consequence of the in situ formation of hafnon (HfSiO4), which represents a concurrent reaction to the carbothermal decomposition of the SiOC matrix. Thus, by the annealing of SiOC/HfO2 materials at 1600°C, novel HfSiO4/SiC/C ceramic nanocomposites can be generated. The results presented emphasize the potential of these materials for application at high temperatures.

Item Type: Article
Erschienen: 2010
Creators: Ionescu, Emanuel and Papendorf, Benjamin and Kleebe, Hans-Joachim and Riedel, Ralf
Title: Polymer-Derived Silicon Oxycarbide/Hafnia Ceramic Nanocomposites. Part II: Stability Toward Decomposition and Microstructure Evolution at T≫1000°C
Language: English
Abstract:

This study presents first investigations on the high-temperature stability and microstructure evolution of SiOC/HfO2 ceramic nanocomposites. Polymer-derived SiOC/HfO2 ceramic nanocomposites have been prepared via chemical modification of a commercially available polysilsesquioxane by hafnium tetra (n-butoxide). The modified polysilsesquioxane-based materials were cross-linked and subsequently pyrolyzed at 1100°C in argon atmosphere to obtain SiOC/HfO2 ceramic nanocomposites. Annealing experiments at temperatures between 1300° and 1600°C were performed and the annealed materials were investigated with respect to chemical composition and microstructure. The ceramic nanocomposites presented here were found to exhibit a remarkably improved thermal stability up to 1600°C in comparison with hafnia-free silicon oxycarbide. Chemical analysis, X-ray diffraction, FTIR, and Raman spectroscopy as well as electron microscopy (SEM, TEM) studies revealed that the excellent thermal stability of the SiOC/HfO2 nanocomposites is a consequence of the in situ formation of hafnon (HfSiO4), which represents a concurrent reaction to the carbothermal decomposition of the SiOC matrix. Thus, by the annealing of SiOC/HfO2 materials at 1600°C, novel HfSiO4/SiC/C ceramic nanocomposites can be generated. The results presented emphasize the potential of these materials for application at high temperatures.

Journal or Publication Title: Journal of the American Ceramic Society
Volume: 93
Number: 6
Publisher: Wiley
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: 11 Apr 2012 11:23
Official URL: http://dx.doi.org/10.1111/j.1551-2916.2009.03527.x
Identification Number: doi:10.1111/j.1551-2916.2009.03527.x
Funders: Financial support by Fonds der Chemischen Industrie.
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