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Phase separation of a hafnium alkoxide-modified polysilazane upon polymer-to-ceramic transformation—A case study

Ionescu, Emanuel and Papendorf, Benjamin and Kleebe, Hans-Joachim and Breitzke, Hergen and Nonnenmacher, Katharina and Buntkowsky, Gerd and Riedel, Ralf (2011):
Phase separation of a hafnium alkoxide-modified polysilazane upon polymer-to-ceramic transformation—A case study.
In: Journal of the European Ceramic Society, ECERS, ISSN 09552219,
[Online-Edition: http://dx.doi.org/10.1016/j.jeurceramsoc.2011.09.003],
[Article]

Abstract

The polymer-to-ceramic transformation of a hafnium alkoxide-modified polysilazane was investigated via thermogravimetric analysis coupled with in situ mass spectrometry (TG/MS), nuclear magnetic resonance (MAS NMR) and transmission electron microscopy (TEM). The results indicate that the structural evolution of the polysilazane upon ceramization is strongly affected by the modification with hafnium alkoxide. Thus, the content of carbon in the ceramic backbone was relatively low, whereas a large amount of SiN4 sites and a segregated carbon phase was present in the sample. Furthermore, this study revealed the formation of a SiHfCNO amorphous single phase ceramic via pyrolysis of the polymer at 700 °C, whereas at higher pyrolysis temperatures precipitation of hafnia was observed, leading to an amorphous hafnia/silicon carbonitride ceramic nanocomposite. The precipitation of hafnia was shown to not rely on decomposition processes, but to be a result of rearrangement reactions occurring within the ceramic material.

Item Type: Article
Erschienen: 2011
Creators: Ionescu, Emanuel and Papendorf, Benjamin and Kleebe, Hans-Joachim and Breitzke, Hergen and Nonnenmacher, Katharina and Buntkowsky, Gerd and Riedel, Ralf
Title: Phase separation of a hafnium alkoxide-modified polysilazane upon polymer-to-ceramic transformation—A case study
Language: English
Abstract:

The polymer-to-ceramic transformation of a hafnium alkoxide-modified polysilazane was investigated via thermogravimetric analysis coupled with in situ mass spectrometry (TG/MS), nuclear magnetic resonance (MAS NMR) and transmission electron microscopy (TEM). The results indicate that the structural evolution of the polysilazane upon ceramization is strongly affected by the modification with hafnium alkoxide. Thus, the content of carbon in the ceramic backbone was relatively low, whereas a large amount of SiN4 sites and a segregated carbon phase was present in the sample. Furthermore, this study revealed the formation of a SiHfCNO amorphous single phase ceramic via pyrolysis of the polymer at 700 °C, whereas at higher pyrolysis temperatures precipitation of hafnia was observed, leading to an amorphous hafnia/silicon carbonitride ceramic nanocomposite. The precipitation of hafnia was shown to not rely on decomposition processes, but to be a result of rearrangement reactions occurring within the ceramic material.

Journal or Publication Title: Journal of the European Ceramic Society
Publisher: ECERS
Uncontrolled Keywords: Precursors, Polymer-derived ceramics (PDCs), Nanocomposites, Transition metal oxides
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Earth Science
11 Department of Materials and Earth Sciences > Earth Science > Geo-Material-Science
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
Date Deposited: 02 Apr 2012 11:18
Official URL: http://dx.doi.org/10.1016/j.jeurceramsoc.2011.09.003
Identification Number: doi:10.1016/j.jeurceramsoc.2011.09.003
Funders: German Research Fundation (DFG) within the Priority Programme SPP1181 NANOMAT (IO64/1–2), Ministry of Higher Education, Research and the Arts in Hesse, Germany (AdRIA: Adaptronik – Research, Innovation, Application), Fonds der Chemischen Industrie for continuous financial support
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