Papendorf, Benjamin ; Nonnenmacher, Katharina ; Ionescu, Emanuel ; Kleebe, Hans-Joachim ; Riedel, Ralf (2011)
Strong Influence of Polymer Architecture on the Microstructural Evolution of Hafnium-Alkoxide-Modified Silazanes upon Ceramization.
In: Small, 7 (7)
doi: 10.1002/smll.201001938
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
The present study focuses on the synthesis and ceramization of novel hafnium-alkoxide-modified silazanes as well as on their microstructure evolution at high temperatures. The synthesis of hafnia-modified polymer-derived SiCN ceramic nanocomposites is performed via chemical modification of a polysilazane and of a cyclotrisilazane, followed by cross-linking and pyrolysis in argon atmosphere. Spectroscopic investigation (i.e., NMR, FTIR, and Raman) shows that the hafnium alkoxide reacts with the N–H groups of the cyclotrisilazane; in the case of polysilazane, reactions of N–H as well as Si–H groups with the alkoxide are observed. Consequently, scanning and transmission electron microscopy studies reveal that the ceramic nanocomposites obtained from cyclotrisilazane and polysilazane exhibited markedly different microstructures, which is a result of the different reaction pathways of the hafnium alkoxide with cyclotrisilazane and with polysilazane. Furthermore, the two prepared ceramic nanocomposites are unexpectedly found to exhibit extremely different high-temperature behavior with respect to decomposition and crystallization; this essential difference is found to be related to the different distribution of hafnium throughout the ceramic network in the two samples. Thus, the homogeneous distribution of hafnium observed in the polysilazane-derived ceramic leads to an enhanced thermal stability with respect to decomposition, whereas the local enrichment of hafnium within the matrix of the cyclotrisilazane-based sample induces a pronounced decomposition upon annealing at high temperatures. The results indicate that the chemistry and architecture of the precursor has a crucial effect on the microstructure of the resulting ceramic material and consequently on its high-temperature behavior
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2011 |
| Autor(en): | Papendorf, Benjamin ; Nonnenmacher, Katharina ; Ionescu, Emanuel ; Kleebe, Hans-Joachim ; Riedel, Ralf |
| Art des Eintrags: | Bibliographie |
| Titel: | Strong Influence of Polymer Architecture on the Microstructural Evolution of Hafnium-Alkoxide-Modified Silazanes upon Ceramization |
| Sprache: | Englisch |
| Publikationsjahr: | 4 April 2011 |
| Verlag: | Wiley |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Small |
| Jahrgang/Volume einer Zeitschrift: | 7 |
| (Heft-)Nummer: | 7 |
| DOI: | 10.1002/smll.201001938 |
| URL / URN: | https://onlinelibrary.wiley.com/doi/10.1002/smll.201001938 |
| Kurzbeschreibung (Abstract): | The present study focuses on the synthesis and ceramization of novel hafnium-alkoxide-modified silazanes as well as on their microstructure evolution at high temperatures. The synthesis of hafnia-modified polymer-derived SiCN ceramic nanocomposites is performed via chemical modification of a polysilazane and of a cyclotrisilazane, followed by cross-linking and pyrolysis in argon atmosphere. Spectroscopic investigation (i.e., NMR, FTIR, and Raman) shows that the hafnium alkoxide reacts with the N–H groups of the cyclotrisilazane; in the case of polysilazane, reactions of N–H as well as Si–H groups with the alkoxide are observed. Consequently, scanning and transmission electron microscopy studies reveal that the ceramic nanocomposites obtained from cyclotrisilazane and polysilazane exhibited markedly different microstructures, which is a result of the different reaction pathways of the hafnium alkoxide with cyclotrisilazane and with polysilazane. Furthermore, the two prepared ceramic nanocomposites are unexpectedly found to exhibit extremely different high-temperature behavior with respect to decomposition and crystallization; this essential difference is found to be related to the different distribution of hafnium throughout the ceramic network in the two samples. Thus, the homogeneous distribution of hafnium observed in the polysilazane-derived ceramic leads to an enhanced thermal stability with respect to decomposition, whereas the local enrichment of hafnium within the matrix of the cyclotrisilazane-based sample induces a pronounced decomposition upon annealing at high temperatures. The results indicate that the chemistry and architecture of the precursor has a crucial effect on the microstructure of the resulting ceramic material and consequently on its high-temperature behavior |
| Freie Schlagworte: | Preceramic polymers, polysilazanes, polymeric materials, ceramics, nanocomposites, microstructure evolution |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Geowissenschaften > Fachgebiet Geomaterialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Disperse Feststoffe |
| Hinterlegungsdatum: | 04 Apr 2012 11:19 |
| Letzte Änderung: | 16 Aug 2021 12:13 |
| PPN: | |
| Export: | |
| Suche nach Titel in: | TUfind oder in Google |
 |
Frage zum Eintrag |
Optionen (nur für Redakteure)
 |
Redaktionelle Details anzeigen |
Drucken
Impressum