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Polymer-Derived Silicon Oxycarbide/Hafnia Ceramic Nanocomposites. Part I: Phase and Microstructure Evolution During the Ceramization Process

Ionescu, Emanuel and Papendorf, Benjamin and Kleebe, Hans-Joachim and Poli, Fabrizia and Müller, Klaus and Riedel, Ralf (2010):
Polymer-Derived Silicon Oxycarbide/Hafnia Ceramic Nanocomposites. Part I: Phase and Microstructure Evolution During the Ceramization Process.
In: Journal of the American Ceramic Society, 93 (6), Wiley, pp. 1774-1782, ISSN 00027820,
[Online-Edition: http://dx.doi.org/10.1111/j.1551-2916.2010.03765.x],
[Article]

Abstract

Polymer-derived SiOC/HfO2 ceramic nanocomposites were prepared via chemical modification of a commercially available polysilsesquioxane by hafnium tetra (n-butoxide). The ceramization process of the starting materials was investigated using thermal analysis and in situ Fourier-transformed infrared spectroscopy and mass spectrometry. Furthermore, solid-state NMR, elemental analysis, powder X-ray diffraction, and electron microscopy investigations were performed on ceramic materials pyrolyzed at different temperatures ranging from 800° to 1300°C, in order to obtain information about the structural changes and phase evolution thereof. The hafnium alkoxide-modified precursor was shown to convert into an amorphous single-phase SixHfyOzCw ceramic at temperatures up to 800°C. By increasing the temperature to 1000°C, amorphous hafnia begins to precipitate throughout the silicon oxycarbide matrix; thus, monodisperse hafnia particles with a diameter of <5 nm are present in the ceramic, indicating a homogeneous nucleation of HfO2. At temperatures ranging from 1100° to 1300°C, crystallization of the hafnia nanoprecipitates as well as phase separation of the SiOC matrix occur. The chemical modification of the preceramic precursor with hafnium alkoxide can be considered as a promising method for the preparation of SiOC/HfO2 nanocomposites with well-dispersed hafnia nanoparticles.

Item Type: Article
Erschienen: 2010
Creators: Ionescu, Emanuel and Papendorf, Benjamin and Kleebe, Hans-Joachim and Poli, Fabrizia and Müller, Klaus and Riedel, Ralf
Title: Polymer-Derived Silicon Oxycarbide/Hafnia Ceramic Nanocomposites. Part I: Phase and Microstructure Evolution During the Ceramization Process
Language: English
Abstract:

Polymer-derived SiOC/HfO2 ceramic nanocomposites were prepared via chemical modification of a commercially available polysilsesquioxane by hafnium tetra (n-butoxide). The ceramization process of the starting materials was investigated using thermal analysis and in situ Fourier-transformed infrared spectroscopy and mass spectrometry. Furthermore, solid-state NMR, elemental analysis, powder X-ray diffraction, and electron microscopy investigations were performed on ceramic materials pyrolyzed at different temperatures ranging from 800° to 1300°C, in order to obtain information about the structural changes and phase evolution thereof. The hafnium alkoxide-modified precursor was shown to convert into an amorphous single-phase SixHfyOzCw ceramic at temperatures up to 800°C. By increasing the temperature to 1000°C, amorphous hafnia begins to precipitate throughout the silicon oxycarbide matrix; thus, monodisperse hafnia particles with a diameter of <5 nm are present in the ceramic, indicating a homogeneous nucleation of HfO2. At temperatures ranging from 1100° to 1300°C, crystallization of the hafnia nanoprecipitates as well as phase separation of the SiOC matrix occur. The chemical modification of the preceramic precursor with hafnium alkoxide can be considered as a promising method for the preparation of SiOC/HfO2 nanocomposites with well-dispersed hafnia nanoparticles.

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: 05 Apr 2012 11:28
Official URL: http://dx.doi.org/10.1111/j.1551-2916.2010.03765.x
Identification Number: doi:10.1111/j.1551-2916.2010.03765.x
Funders: Deutsche Forschungsgemeinschaft (DFG) for the financial support of this work (Priority Program SPP 1181), Fonds der Chemischen Industrie for additional financial support, Financial support by the DFG (MU 1166/12-2)
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