Li, Y.-L. ; Kroke, E. ; Riedel, R. ; Fasel, C. ; Gervais, C. ; Babonneau, F. (2001)
Thermal cross-linking and pyrolytic conversion of poly(ureamethylvinyl)silazanes to silicon-based ceramics.
In: Applied organometallic chemistry, 15 (10)
Article, Bibliographie
Abstract
The aim of this work was to study the pyrolytic conversion of a novel commercial polysilazane, poly(ureamethylvinyl)silazane (PUMVS; Ceraset™, Allied Signal Composites Inc., USA), into silicon-based ceramics. The precursor was thermally cross-linked and pyrolyzed between 200 and 1700 °C under argon or nitrogen atmosphere and the products were investigated by spectroscopic techniques (FTIR and Raman spectroscopy, solid-state NMR), elemental analysis and simultaneous thermal analysis coupled with mass spectrometry. Upon heating under argon, the starting liquid precursor transformed into an infusible solid polymer at T > 250 °C with a conversion yield of >95 wt%. The cross-linking solidification occurred predominantly through hydrosilylation or addition reaction involving vinyl groups. Subsequent pyrolysis of the cross-linked products around 1000 °C in argon yielded amorphous silicon carbonitride ceramics with a composition of SiN0.82C0.86. The overall ceramic yield (with respect to the starting PUMVS) was around 70 wt%, which was found to be independent of the initial cross-linking step. Solid-state NMR (29Si and 13C) revealed that the amorphous silicon carbonitrides contain predominately CSiN3 units. There is evidence for the formation of free amorphous carbon between 700 and 800 °C. Graphitic phases were detected by X-ray diffraction in the samples heated to T > 1000 °C at high heating rates. Upon annealing at T > 1500 °C, the excess carbon reacted completely with the silicon (carbo)nitride to form SiC and nitrogen. The final ceramics contained a large amount of crystalline SiC (∼90 wt%), and were free of excess carbon or silicon. Therefore, PUMVS is an ideal precursor for the formation of high-quality SiC-based ceramics.
| Item Type: | Article |
|---|---|
| Erschienen: | 2001 |
| Creators: | Li, Y.-L. ; Kroke, E. ; Riedel, R. ; Fasel, C. ; Gervais, C. ; Babonneau, F. |
| Type of entry: | Bibliographie |
| Title: | Thermal cross-linking and pyrolytic conversion of poly(ureamethylvinyl)silazanes to silicon-based ceramics |
| Language: | English |
| Date: | October 2001 |
| Publisher: | Wiley |
| Journal or Publication Title: | Applied organometallic chemistry |
| Volume of the journal: | 15 |
| Issue Number: | 10 |
| Abstract: | The aim of this work was to study the pyrolytic conversion of a novel commercial polysilazane, poly(ureamethylvinyl)silazane (PUMVS; Ceraset™, Allied Signal Composites Inc., USA), into silicon-based ceramics. The precursor was thermally cross-linked and pyrolyzed between 200 and 1700 °C under argon or nitrogen atmosphere and the products were investigated by spectroscopic techniques (FTIR and Raman spectroscopy, solid-state NMR), elemental analysis and simultaneous thermal analysis coupled with mass spectrometry. Upon heating under argon, the starting liquid precursor transformed into an infusible solid polymer at T > 250 °C with a conversion yield of >95 wt%. The cross-linking solidification occurred predominantly through hydrosilylation or addition reaction involving vinyl groups. Subsequent pyrolysis of the cross-linked products around 1000 °C in argon yielded amorphous silicon carbonitride ceramics with a composition of SiN0.82C0.86. The overall ceramic yield (with respect to the starting PUMVS) was around 70 wt%, which was found to be independent of the initial cross-linking step. Solid-state NMR (29Si and 13C) revealed that the amorphous silicon carbonitrides contain predominately CSiN3 units. There is evidence for the formation of free amorphous carbon between 700 and 800 °C. Graphitic phases were detected by X-ray diffraction in the samples heated to T > 1000 °C at high heating rates. Upon annealing at T > 1500 °C, the excess carbon reacted completely with the silicon (carbo)nitride to form SiC and nitrogen. The final ceramics contained a large amount of crystalline SiC (∼90 wt%), and were free of excess carbon or silicon. Therefore, PUMVS is an ideal precursor for the formation of high-quality SiC-based ceramics. |
| Uncontrolled Keywords: | pyrolysis, polysilazane, ceramics, SiC, Ceraset™ |
| Divisions: | 11 Department of Materials and Earth Sciences 11 Department of Materials and Earth Sciences > Material Science 11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids |
| Date Deposited: | 19 Nov 2008 16:27 |
| Last Modified: | 20 Feb 2020 13:27 |
| PPN: | |
| Funders: | Funded by Deutsche Forschungsgemeinschaft and Fonds der Chemischen Industrie |
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