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In-situ carbon content adjustment in polymer-derived Si/C/N ceramics by reactive heat treatment. Calculations of the pyrolysis product composition

Galusek, D. ; Reschke, S. ; Riedel, R. :
In-situ carbon content adjustment in polymer-derived Si/C/N ceramics by reactive heat treatment. Calculations of the pyrolysis product composition.
In: Silicate industriels, 64 (1-2) pp. 3-7. ISSN 0037-5225
[Artikel], (1999)

Kurzbeschreibung (Abstract)

A simplified mechanistic approach has been developed to estimate the range of compositional changes during the reactive heat treatment of different preceramic organosilicon precursors resulting in their conversion to amorphous Si/C/N ceramics. The calculations use the compositions of the respective crosslinked polyilazanes as starting values and combine the conversion degrees of chemical reactions with the highest thermodynamical probability taking part during heat treatment. This approach allows to estimate a processing-dependend stoichiometry of the Si/C/N ceramics, assuming the reactions yield thermodynamically stable equilibrium products. Calculated data are consistent with experimental results and indicate, that the stoichiometry of the product is determined by structure and chemical composition of the polymer rather than by the conditions applied during heat treatment. However, within the restrictions through the chemistry of the polymer, the stoichiometry of the productcan be controlled by proper adjustment of the experimental conditions.

Typ des Eintrags: Artikel
Erschienen: 1999
Autor(en): Galusek, D. ; Reschke, S. ; Riedel, R.
Titel: In-situ carbon content adjustment in polymer-derived Si/C/N ceramics by reactive heat treatment. Calculations of the pyrolysis product composition
Sprache: Englisch
Kurzbeschreibung (Abstract):

A simplified mechanistic approach has been developed to estimate the range of compositional changes during the reactive heat treatment of different preceramic organosilicon precursors resulting in their conversion to amorphous Si/C/N ceramics. The calculations use the compositions of the respective crosslinked polyilazanes as starting values and combine the conversion degrees of chemical reactions with the highest thermodynamical probability taking part during heat treatment. This approach allows to estimate a processing-dependend stoichiometry of the Si/C/N ceramics, assuming the reactions yield thermodynamically stable equilibrium products. Calculated data are consistent with experimental results and indicate, that the stoichiometry of the product is determined by structure and chemical composition of the polymer rather than by the conditions applied during heat treatment. However, within the restrictions through the chemistry of the polymer, the stoichiometry of the productcan be controlled by proper adjustment of the experimental conditions.

Titel der Zeitschrift, Zeitung oder Schriftenreihe: Silicate industriels
Band: 64
(Heft-)Nummer: 1-2
Freie Schlagworte: precursor, polymer pyrolysis, NH3, Si/N(/C), amorphous ceramics, calculations, poly(hydridomethyl)silazanes, polyvinylsilazanes, polymethyldisilazanes
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 15:58
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