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Thermal decomposition of poly(methylsilsesquecarbodiimide) to amorphous Si-C-N-ceramics

Gabriel, Andreas O. ; Riedel, R. ; Dreßler, W. ; Reichert, S. ; Gervais, C. ; Maquet, J. ; Babonneau, F. :
Thermal decomposition of poly(methylsilsesquecarbodiimide) to amorphous Si-C-N-ceramics.
In: Chemistry of materials, 11 (2) pp. 412-420.
[Artikel], (1999)

Kurzbeschreibung (Abstract)

This paper is based on the recent discovery that the thermal decomposition of poly(methylsilsesquicarbodiimide), [CH3Si(NCN)1.5]n, leads to amorphous silicon carbonitride (SiCN) ceramics. In the present study the polymer-to-ceramic transformation is characterized using analytical and spectroscopic methods. In particular, the structural transition from the molecular precursor to the final amorphous SiCN ceramic was studied by solid-state NMR spectroscopy. The coordination of the silicon atoms changes from CH3−Si(−NCN−)3 in the polysilylcarbodiimide precursor at room temperature to Si(−N<)4 in the X-ray amorphous reaction product formed at 1200 °C. This result implies the formation of amorphous silicon nitride (Si3N4). The remaining weight fraction is analyzed to be elemental carbon. According to bulk chemical analysis, the poly(methylsilsesquicarbodiimide)-derived SiCN is comprised of a mixture of 1 mol amorphous Si3N4 with 3 mol amorphous carbon. The molar ratio Si3N4/C = 1/3 is suitable for the formation of stoichiometric silicon carbide, which is expected thermodynamically at temperatures exceeding 1440 °C in 0.1 MPa N2. The pyrolysis behavior of the poly(silylcarbodiimide) and the formation of silicon carbonitride ceramics are compared to those of poly(silazanes).

Typ des Eintrags: Artikel
Erschienen: 1999
Autor(en): Gabriel, Andreas O. ; Riedel, R. ; Dreßler, W. ; Reichert, S. ; Gervais, C. ; Maquet, J. ; Babonneau, F.
Titel: Thermal decomposition of poly(methylsilsesquecarbodiimide) to amorphous Si-C-N-ceramics
Sprache: Englisch
Kurzbeschreibung (Abstract):

This paper is based on the recent discovery that the thermal decomposition of poly(methylsilsesquicarbodiimide), [CH3Si(NCN)1.5]n, leads to amorphous silicon carbonitride (SiCN) ceramics. In the present study the polymer-to-ceramic transformation is characterized using analytical and spectroscopic methods. In particular, the structural transition from the molecular precursor to the final amorphous SiCN ceramic was studied by solid-state NMR spectroscopy. The coordination of the silicon atoms changes from CH3−Si(−NCN−)3 in the polysilylcarbodiimide precursor at room temperature to Si(−N<)4 in the X-ray amorphous reaction product formed at 1200 °C. This result implies the formation of amorphous silicon nitride (Si3N4). The remaining weight fraction is analyzed to be elemental carbon. According to bulk chemical analysis, the poly(methylsilsesquicarbodiimide)-derived SiCN is comprised of a mixture of 1 mol amorphous Si3N4 with 3 mol amorphous carbon. The molar ratio Si3N4/C = 1/3 is suitable for the formation of stoichiometric silicon carbide, which is expected thermodynamically at temperatures exceeding 1440 °C in 0.1 MPa N2. The pyrolysis behavior of the poly(silylcarbodiimide) and the formation of silicon carbonitride ceramics are compared to those of poly(silazanes).

Titel der Zeitschrift, Zeitung oder Schriftenreihe: Chemistry of materials
Band: 11
(Heft-)Nummer: 2
Verlag: ACS
Fachbereich(e)/-gebiet(e): Fachbereich Material- und Geowissenschaften > Materialwissenschaften > Disperse Feststoffe, Dispersive Solids
Fachbereich Material- und Geowissenschaften > Materialwissenschaften
Fachbereich Material- und Geowissenschaften
Hinterlegungsdatum: 19 Nov 2008 16:23
Sponsoren: The authors gratefully acknowledge the Deutsche Forschungsgemeinschaft (DFG), Bonn, Germany, the Fonds der Chemischen Industrie, Frankfurt, Germany for financial support, as well as the Deutsche Akademische Austauschdienst (Bonn, Germany), and the Ministe`re des Affaires Etrange`res (Paris, France) through the Procope collaborative exchange program. CM980747C
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